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Network

Visa

Code

12.4

Response window

30 calendar days

Win difficulty

Medium

Dispute type

Processing Error

Visa 12.4 — Incorrect Account Number: What It Is and How to Respond

Note: Most 12.4 disputes are caused by merchant-side key entry errors or software issues. Check your authorisation and settlement records first — if the wrong account number was processed on your end, accept the chargeback rather than contest it.

Visa 12.4 is filed when a transaction is posted to an account number that does not match the card number authorised. This can happen through manual key entry errors, processing software bugs, or account number tokenisation mismatches. The correct cardholder’s card was either over-charged or a different cardholder was charged entirely.

Whether you can contest this dispute depends entirely on your records: if your authorisation shows the correct account number and the settlement file matches, the error may have occurred downstream at the processor or network. If your own system sent the wrong account number, accept the chargeback and correct the error.

Common reasons you received this dispute

  1. 1Manual key entry of a card number resulted in a transposition error
  2. 2Account tokenisation mapped to the wrong stored card in your payment system
  3. 3A card reissue (new number after expiry or replacement) was not reflected in your stored token records
  4. 4A customer with multiple saved payment methods had the wrong one charged
  5. 5A legacy payment system bug with account number handling during batch settlement

Can you win this dispute?

Fight this dispute if...

  • ✓Your transaction records show the correct account number was used for both authorisation and settlement, and the dispute is a processing error on the issuer's or network's side
  • ✓The cardholder has confused two different accounts — your records clearly show the authorised account matches the one that was charged
  • ✓You have documentation from your payment processor confirming the account number transmitted was correct

Accept this chargeback if...

  • ✗Your records confirm the wrong account number was processed — particularly if a key entry error or software bug caused the wrong card to be charged
  • ✗A tokenisation mapping error in your system resulted in the wrong stored card being billed
  • ✗A card reissue update was not applied correctly and the old (or wrong) card number was charged

Evidence checklist

  1. ✅ Required

    Original authorisation record showing the account number authorised: The authorisation response clearly showing the card/account number that was approved by the issuer.

  2. ✅ Required

    Settlement record showing account number processed: The settlement file or processor confirmation showing the account number submitted for settlement, to compare with the authorisation.

  3. ✅ Required

    Cardholder record showing their registered payment method: Your customer account record showing which card or payment method was associated with this transaction at the time it was made.

  4. ⭐ Strongly recommended

    Payment system transaction log: A detailed log from your payment system showing the account number at each stage of processing — entry, authorisation request, response, and settlement submission.

  5. ⭐ Strongly recommended

    Tokenisation mapping records (if applicable): If your system uses tokenisation, the mapping record showing which card number the token resolves to at the time of the transaction.

How to write your response

Your response must show that the account number used for authorisation matches the account number used for settlement, and that both match the cardholder’s registered payment method. Present each record as a numbered exhibit and make the comparison explicit.

If the dispute involves a tokenisation system, explain briefly how the token maps to the card number and include the mapping record. Keep the narrative focused on the account number match — that is the only question the dispute reviewer needs answered.

“We are responding to chargeback [reference] under Visa code 12.4. Exhibit A shows the original authorisation record confirming the transaction was authorised for account ending [XXXX]. Exhibit B shows the settlement record — the account number submitted for settlement matches the authorisation. Exhibit C shows our customer record confirming the cardholder’s registered payment method on file as of [date]. All three records are consistent. We request reversal of this chargeback.”

Key deadlines

Response window: 30 calendar days from the chargeback notification date.

Retain authorisation records, settlement files, and tokenisation mapping records for at least 18 months to cover potential dispute windows.

Account number mismatches between authorisation and settlement are detectable through daily reconciliation — catching these early can prevent the dispute from being raised at all.

How to prevent this chargeback

  1. 1

    Minimise manual card number entry: Use card readers, hosted payment fields, tokenisation, and saved payment methods instead of manual key entry wherever possible. Manual entry is the single largest source of account number errors.

  2. 2

    Display masked card numbers at checkout: For customers with stored payment methods, display a masked card number (e.g. ending in 4242) at the checkout confirmation screen so they can verify the correct card is selected before completing payment.

  3. 3

    Validate tokenisation records after card reissues: When a card is reissued with a new number, your tokenisation provider should update the mapping automatically. Audit these updates periodically to confirm the token-to-card-number mappings are current.

  4. 4

    Reconcile daily — account number mismatches appear in settlement reports: A daily settlement-vs-authorisation reconciliation will surface any account number discrepancies before the dispute window opens, giving you time to proactively refund and correct.

Frequently asked questions

What is a Visa 12.4 chargeback?

Visa 12.4 is a processing error dispute raised when a transaction is posted to an account number that does not match the card number that was authorised. This can result from manual key entry errors, tokenisation mismatches, or software bugs that caused the wrong stored card to be charged.

Is this usually the merchant's fault?

Yes, most Visa 12.4 disputes stem from merchant-side errors — manual key entry transposition mistakes, tokenisation mapping issues, or software bugs. Only in rare cases is the error attributable to the issuer or network. Be honest about the source of the error before deciding whether to contest.

What if a customer has multiple saved cards and the wrong one was charged?

Ensure your checkout clearly shows a masked version of the card being charged (e.g. ending in 4242) so the cardholder can confirm the correct card before completing payment. If the wrong card was charged due to a UI or system error on your side, accept the chargeback.

How long do I have to respond to a Visa 12.4 chargeback?

30 calendar days from the chargeback notification date. Pull your authorisation records and transaction logs immediately to determine whether the correct account number was used before deciding whether to contest.

Related reason codes

Visa 12.5

Incorrect Amount

Visa 12.2

Incorrect Transaction Code

Visa 12.6.1

Duplicate Processing

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