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External Host Interface Integration Guide

13. Chargeback and Chargeback Reversal Messages

Chargeback messages are sent when a dispute-related financial event occurs after a transaction has already been presented. A chargeback can only be created for a transaction that has a linked presentment. In the EHI transaction flow, a chargeback notification is sent to your system, and your system returns an acknowledgement.

As with all EHI messages, Payblr forwards the EHI JSON payload to your configured endpoint. Your system should process the message using the EHI fields, optionally match it to the related financial notification or chargeback, and update dispute, ledger, and reconciliation records according to your internal rules.

Chargeback messages are different from authorization, authorization reversal, and financial reversal messages. They are dispute-related financial notifications and should not be treated as new authorization requests.

Note: For the Payblr integration, document chargeback processing using 1240 / H for chargeback notification and 1240 / K for chargeback reversal.

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13.1 Applicable identifiers

Chargeback and chargeback reversal messages are identified using the EHI fields included in the forwarded JSON payload.

FieldExpected valueDescription
MTID1240Identifies the message as a financial notification type.
Txn_TypeHIdentifies a chargeback notification, non-credit.
Txn_TypeKIdentifies a chargeback reversal.
TokenVariesIdentifies the card token associated with the transaction.
TXn_ID / Txn_IDVariesIdentifies the EHI transaction message.
Acquirer_Reference_Data_031Varies, when presentMay be used to match the chargeback to the financial notification.
Auth_Code_DE38Varies, when presentMay help match the chargeback to the financial notification.
Trans_LinkVaries, when presentMay help match the chargeback to the financial notification or related chargeback.
Reason_IDVaries, when presentIndicates the chargeback reason.
Dispute_ConditionVaries, when presentProvides additional dispute reason information for chargeback message.
Network_Chargeback_Reference_IdVaries, when presentNetwork chargeback reference identifier.

1240 / H identifies a chargeback notification, non-credit, and 1240 / K identifies a chargeback reversal.

13.2 Chargeback flow

Chargeback flow

Platform

Payblr

System

Your Systems

1. Forward original EHI chargeback payload

Chargeback

Payblr forwards the original EHI chargeback payload to your configured endpoint.

PayblrYour Systems

2. Validate Payblr request signature and timestamp

Your system validates the Payblr request signature and timestamp before processing.

Your SystemsprocessesYour Systems

3. Identify chargeback using MTID=1240 and Txn_Type=H

Your system identifies the chargeback using MTID=1240 and Txn_Type=H.

Your SystemsprocessesYour Systems

4. Check whether chargeback was already processed

Your system checks whether the chargeback was already processed to keep handling idempotent.

Your SystemsprocessesYour Systems

5. Optionally match to related financial notification

Your system optionally matches the chargeback to a related financial notification.

Your SystemsprocessesYour Systems

6. Update dispute, ledger, and reconciliation records

Chargeback

Your system updates dispute, ledger, and reconciliation records.

Your SystemsprocessesYour Systems

7. Return acknowledgement response

Chargeback

Your system returns the required acknowledgement response to Payblr.

Your SystemsPayblr

8. Relay acknowledgement through the transaction flow

Payblr relays the acknowledgement through the transaction flow.

PayblrprocessesPayblr
sequenceLaneCenter(index, columnCount)

13.3 Chargeback reversal flow

Chargeback reversal flow

Platform

Payblr

System

Your Systems

1. Forward original EHI chargeback reversal payload

Chargeback reversal

Payblr forwards the original EHI chargeback reversal payload to your configured endpoint.

PayblrYour Systems

2. Validate Payblr request signature and timestamp

Your system validates the Payblr request signature and timestamp before processing.

Your SystemsprocessesYour Systems

3. Identify chargeback reversal using MTID=1240 and Txn_Type=K

Your system identifies the chargeback reversal using MTID=1240 and Txn_Type=K.

Your SystemsprocessesYour Systems

4. Check whether reversal was already processed

Your system checks whether the reversal was already processed to keep handling idempotent.

Your SystemsprocessesYour Systems

5. Optionally match to original chargeback

Your system optionally matches the reversal to the original chargeback.

Your SystemsprocessesYour Systems

6. Reverse or adjust chargeback-related impact

Chargeback reversal

Your system reverses or adjusts the chargeback-related impact.

Your SystemsprocessesYour Systems

7. Return acknowledgement response

Chargeback reversal

Your system returns the required acknowledgement response to Payblr.

Your SystemsPayblr

8. Relay acknowledgement through the transaction flow

Payblr relays the acknowledgement through the transaction flow.

PayblrprocessesPayblr
sequenceLaneCenter(index, columnCount)

13.4 How your system should process chargeback messages

When your system receives a chargeback message, they should:

  1. Validate Payblr’s integration headers, signature, timestamp, and original EHI JSON payload before processing.
  2. Identify the message as a chargeback using MTID = 1240 and Txn_Type = H.
  3. Check whether the chargeback message was already received or processed using the applicable EHI identifiers.
  4. Optionally match the chargeback to the related financial notification using the EHI matching criteria.
  5. Review dispute-related fields such as Reason_ID, Dispute_Condition, and Network_Chargeback_Reference_Id, when present.
  6. Update dispute, ledger, transaction history, and reconciliation records according to your internal rules.
  7. If no matching financial notification is found, store the chargeback as unmatched and process it according to your reconciliation or exception-handling process.
  8. Return the required acknowledgement response.
  9. Store the chargeback message, matching result, response returned, and x-correlation-id for audit, duplicate handling, and reconciliation.

13.5 How your system should process chargeback reversal messages

When your system receives a chargeback reversal message, they should:

  1. Validate Payblr’s integration headers, signature, timestamp, and EHI JSON payload before processing.
  2. Identify the message as a chargeback reversal using MTID = 1240 and Txn_Type = K.
  3. Check whether the chargeback reversal was already received or processed.
  4. Optionally match the chargeback reversal to the original 1240 / H chargeback message.
  5. Reverse or adjust the previous chargeback-related ledger or dispute impact according to your internal rules.
  6. If no matching chargeback is found, store the chargeback reversal as unmatched and process it according to your reconciliation or exception-handling process.
  7. Return the required acknowledgement response.
  8. Store the chargeback reversal message, matching result, response returned, and x-correlation-id for audit, duplicate handling, and reconciliation.

A 1240 / K chargeback reversal reverses the effect of a chargeback, for example reversing the impact on the account balance if the original chargeback changed it.

13.6 Chargeback matching criteria

Your system may match chargeback notifications to the related financial notification using the original EHI fields.

Incoming messageMatch toMatching criteria
1240 / H chargeback notification, non-creditRelated financial notification: 1240 / P or 1200 / WUse the applicable chargeback matching fields when available.

When matching chargeback notifications, your system may use the following fields when available:

Matching fieldMatching criteria
Acquirer_Reference_Data_031OTHER.Acquirer_Reference_Data_031 = THIS.Acquirer_Reference_Data_031
TokenOTHER.Token = THIS.Token
Auth_Code_DE38OTHER.Auth_Code_DE38 = THIS.Auth_Code_DE38, when present
Trans_LinkOTHER.Trans_Link = THIS.Trans_Link

Some fields may be blank or unavailable in certain chargeback messages. Your system should store unmatched chargebacks for reconciliation or exception handling when a reliable match cannot be confirmed.

13.7 Chargeback reversal matching criteria

Your system may match a chargeback reversal to the original chargeback message using the original EHI fields.

Incoming messageMatch toMatching criteria
1240 / K chargeback reversalOriginal 1240 / H chargeback notificationUse the same available matching fields as chargeback matching, except the original matched message has Txn_Type = H.

The matching logic can be understood as:

OTHER.MTID = '1240'
AND OTHER.Txn_Type = 'H'
AND OTHER.Acquirer_Reference_Data_031 = THIS.Acquirer_Reference_Data_031
AND OTHER.Token = THIS.Token
AND OTHER.Auth_Code_DE38 = THIS.Auth_Code_DE38
AND OTHER.Trans_link = THIS.Trans_link

1240 / K follows the same matching approach as chargeback matching, except the original transaction to match has Txn_Type = H.

13.8 Processing outcome

ScenarioRequired handling
Chargeback received and related financial notification foundMatch the chargeback to the financial notification and update dispute, ledger, and reconciliation records.
Chargeback received and no financial match foundStore as unmatched and process through reconciliation or exception handling.
Chargeback non-credit receivedProcess according to your dispute and reconciliation rules.
Chargeback reversal received and original chargeback foundReverse or adjust the original chargeback impact.
Chargeback reversal received and original chargeback not foundStore as unmatched and process through reconciliation or exception handling.
Duplicate chargebackDo not apply dispute, ledger, balance, or reconciliation impact again. Return the same logical acknowledgement.
Duplicate chargeback reversalDo not reverse or adjust the chargeback impact again. Return the same logical acknowledgement.

13.9 Required response

Chargeback and chargeback reversal messages should be acknowledged after your system receives and processes the message.

  • Acknowledgement: Indicates that your system received and processed the chargeback or chargeback reversal message.
  • Responsestatus: Optional. May be included when required by the EHI response contract or program configuration.

For chargeback and chargeback reversal messages, your system generally returns an acknowledgement response instead of a new approve or decline decision.

13.10 Chargeback request examples

Official guide exampleIdentifierUse
ChargebackMTID = 1240, Txn_Type = CUse for chargeback notification reference scenario.
Non-Credit ChargebackMTID = 1240, Txn_Type = HUse for non-credit chargeback notification reference scenario.

Chargeback request example with Txn_Type = C, for Mastercard:

{
  "AuthenticationAmountUpper": 0.0000,
  "FxProviderCardholderRate": 0.0,
  "Network_Chargeback_Reference_Id": "2400000015906",
  "Acquirer_Reference_Data_031": "74600000000000000000000",
  "Currency_Code_Fee": "392",
  "Currency_Code_Fee_Settlement": "392",
  "Interchange_Amount_Fee": -11.1111,
  "Interchange_Amount_Fee_Settlement": -11.1111,
  "DCC_Indicator": 0,
  "multi_part_txn": 0,
  "multi_part_txn_final": 0,
  "multi_part_number": 0,
  "multi_part_count": 0,
  "SettlementIndicator": "0",
  "auth_type": "0",
  "Matching_Txn_ID": 0,
  "Reason_ID": 4001,
  "Merch_Name": "WHATST BANK",
  "Merch_Street": "CHARGEBACK UK HSBC 5",
  "Merch_City": "LONDON",
  "Merch_Region": "GBR",
  "Merch_Country": "GBR",
  "Merch_Postcode": "00000",
  "Merch_Tel": "0",
  "Merch_URL": "0",
  "Merch_Tax_id": "0",
  "GPS_POS_Capability": "000000000000000000000000000000000000000000000000",
  "GPS_POS_Data": "9613000000000",
  "Acquirer_id_DE32": "0000000000",
  "ActBal": 0.00,
  "Auth_Code_DE38": "000000",
  "Avl_Bal": 0.00,
  "Bill_Amt": 0.00,
  "Bill_Ccy": "826",
  "BlkAmt": 0.00,
  "Fee_Fixed": 0.00,
  "Fee_Rate": 0.00,
  "MCC_Code": "6011",
  "Merch_ID_DE42": "000000000000000",
  "Merch_Name_DE43": "WHATST BANK",
  "Proc_Code": "000000",
  "Ret_Ref_No_DE37": "000000000000",
  "Settle_Amt": 0.00,
  "Settle_Ccy": "826",
  "Status_Code": "00",
  "Token": 100000000,
  "Trans_link": "000000000000000000",
  "Txn_Amt": 0.0000,
  "Txn_CCy": "826",
  "Txn_Ctry": "GBR",
  "Txn_Desc": "Chargeback",
  "Txn_GPS_Date": "2026-01-01 00:00:00.000",
  "TXn_ID": 0,
  "Txn_Stat_Code": "A",
  "Txn_Type": "C",
  "MTID": "1240",
  "ProductID": 0,
  "SubBIN": 0,
  "SendingAttemptCount": 0
}

13.11 Chargeback reversal request examples

Official guide exampleIdentifierUse
Chargeback ReversalMTID = 1240, Txn_Type = KUse for chargeback reversal reference scenario.

Chargeback reversal request example with Txn_Type = K, for Mastercard:

{
  "AuthenticationAmountUpper": 0.0000,
  "FxProviderCardholderRate": 0.0,
  "Network_Chargeback_Reference_Id": "2400000015906",
  "Acquirer_Reference_Data_031": "74600000000000000000000",
  "DCC_Indicator": 0,
  "multi_part_txn": 0,
  "multi_part_txn_final": 0,
  "auth_type": "0",
  "Matching_Txn_ID": 0,
  "Reason_ID": 4001,
  "Merch_Name": "WHATST BANK",
  "Merch_Street": "CHARGEBACK UK HSBC 5",
  "Merch_City": "LONDON",
  "Merch_Region": "GBR",
  "Merch_Country": "GBR",
  "GPS_POS_Capability": "000000000000000000000000000000000000000000000000",
  "GPS_POS_Data": "9613000000000",
  "Acquirer_id_DE32": "0000000000",
  "ActBal": 0.00,
  "Auth_Code_DE38": "000000",
  "Avl_Bal": 0.00,
  "Bill_Amt": 0.00,
  "Bill_Ccy": "826",
  "BlkAmt": 0.00,
  "MCC_Code": "6011",
  "Merch_ID_DE42": "000000000000000",
  "Merch_Name_DE43": "WHATST BANK",
  "Proc_Code": "000000",
  "Ret_Ref_No_DE37": "000000000000",
  "Settle_Amt": 0.00,
  "Settle_Ccy": "826",
  "Status_Code": "00",
  "Token": 100000000,
  "Trans_link": "000000000000000000",
  "Txn_Amt": 0.0000,
  "Txn_CCy": "826",
  "Txn_Ctry": "GBR",
  "Txn_Desc": "Chargeback reversal",
  "Txn_GPS_Date": "2026-01-01 00:00:00.000",
  "TXn_ID": 0,
  "Txn_Stat_Code": "A",
  "Txn_Type": "K",
  "MTID": "1240",
  "ProductID": 0,
  "SubBIN": 0,
  "SendingAttemptCount": 0
}

13.12 Response example

Minimal acknowledgement response:

{
  "Acknowledgement": "1"
}

13.13 Implementation notes

  • Chargeback messages should not be treated as authorization requests.
  • Chargeback messages should be processed as dispute-related financial notifications.
  • 1240 / H identifies a chargeback notification, non-credit.
  • 1240 / K identifies a chargeback reversal.
  • Your system may match chargebacks to the related financial notification when possible.
  • Your system may match chargeback reversals to the original 1240 / H chargeback when possible.
  • Your system should use Reason_ID, Dispute_Condition, and Network_Chargeback_Reference_Id when available for dispute and reconciliation handling.
  • If no reliable match is found, your system should store the message and route it to reconciliation or exception handling.
  • Your system should avoid duplicate dispute, ledger, balance, or reconciliation impact if the same chargeback or chargeback reversal is received more than once.
  • Your system should store key identifiers such as Token, TXn_ID, Acquirer_Reference_Data_031, Auth_Code_DE38, Trans_link, Reason_ID, Network_Chargeback_Reference_Id, and x-correlation-id.