Identify the dispute reason code before assembling evidence — Visa, Mastercard, Amex, and Discover each have their own reason code taxonomies; the PSP usually normalizes these but also provides the raw network code, which determines what evidence is compelling.
For 'item not received' or 'services not rendered': provide signed proof of delivery (carrier tracking with destination confirmation), proof of digital delivery (download logs, access timestamps, IP address, email confirmation with open tracking), and any customer communication acknowledging receipt.
For 'fraudulent transaction' or 'card not present fraud': provide AVS and CVV match results, device fingerprint and IP geolocation showing consistency with the cardholder's known location, account login history, and any customer service correspondence post-purchase.
For 'item not as described' or 'quality dispute': provide your published product description, photos or specifications, your refund/return policy displayed at checkout, and any customer service interaction where you attempted to resolve the dispute.
Quantify and include: transaction date and amount, the payment method last 4 digits, billing address used, and a clear narrative letter (1–2 paragraphs) explaining why the dispute is invalid — networks expect a human-readable summary alongside documentary evidence.
Submit all evidence as a single organized package before the deadline; include a cover sheet listing each piece of evidence and the specific claim it refutes, as card network reviewers process high volumes and clear organization improves win rates.
Known gotchas
Card networks apply a per-dispute evidence page limit (often 50 pages or a file size cap around 5 MB across all attachments) — submitting everything you have may cause rejection of the full evidence package if it exceeds limits.
Compelling evidence for Visa disputes changed with the introduction of CE3.0 rules (effective 2023+), which require at least two prior undisputed transactions from the same customer matching specific data points; verify you meet the threshold before relying on this defense.
A refund issued after a dispute is opened does not automatically withdraw the chargeback — you must also communicate the refund to your PSP and in some cases explicitly request a pre-arbitration withdrawal; otherwise both the chargeback and your refund may be processed, resulting in a double loss.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp