Matching your evidence to the exact reason code is the single biggest driver of win rate in representment.
Chargebacks & Disputes: The Glossary and Response Checklist for Merchants
A glossary and response checklist covering chargeback reason codes, representment, and the evidence merchants need to fight disputes.
Chargebacks are inevitable at scale, but a structured response process meaningfully improves win rates. This glossary and checklist covers the terms and steps every merchant ops team needs.
Core glossary
Chargeback — A forced transaction reversal initiated by a cardholder's issuing bank, pulling funds back from the merchant, typically triggered by a customer dispute or fraud claim.
Chargeback reason code — A 2-4 digit alphanumeric code the issuing bank assigns when a chargeback is filed, translating the customer's justification into a standardized category the merchant can address.
Representment — The merchant's formal rebuttal submitted to the issuing bank, presenting documentation that supports the original transaction's validity, filed within the card network's required timeframe.
AVS (Address Verification System) — A check matching the billing address provided at checkout against the address on file with the card issuer, often used as supporting evidence in representment.
Friendly fraud — A chargeback filed by a legitimate cardholder disputing a transaction they actually made, rather than genuine unauthorized fraud.
Reason code categories
Reason codes generally fall into four buckets: fraud (transaction not authorized by the cardholder), authorization issues (transaction processed without proper authorization), consumer disputes (product/service not as described, not received, or subscription cancellation issues), and processing errors (duplicate charges, incorrect amounts).
Response checklist
- Identify the exact reason code — Each network (Visa, Mastercard, Amex, Discover) has its own code system; don't assume categories match across networks.
- Pull evidence matched to that code — Delivery confirmation for "item not received," AVS/CVV match data for fraud claims, refund/cancellation records for subscription disputes.
- Check the network's response deadline — Deadlines vary by network and are typically short (often under 30 days).
- File representment with a clear rebuttal — State plainly why the evidence contradicts the cardholder's claim.
- Track win/loss patterns by reason code — Recurring reason codes often point to a fixable root cause (unclear billing descriptor, slow shipping, weak fraud screening).
Sources
Checkout.com: Chargeback Reason Codes, Chargebacks911: Chargeback Reason Codes — The Ultimate Guide for 2026.
Frequently asked questions
Representment is the formal response a merchant submits to the issuing bank when it believes a chargeback should be reversed, backed by documentation like delivery confirmation, AVS results, or customer communication tied to the specific reason code.
No — Visa, Mastercard, American Express, and Discover each maintain their own reason code systems with distinct categories and response deadlines, so evidence requirements differ by network.
Matching the evidence you submit directly to what the specific reason code requires — generic evidence that doesn't address the stated reason for the dispute rarely succeeds in representment.