Visa 12.6.1 — Duplicate Processing
Processing Error chargeback.
Code
12.6.1 VisaCategory
Processing Error
What it means
The same purchase was charged more than once.
Evidence that wins
Proof of two separate purchases (different orders, items or times).
How to prevent it
Use idempotency keys; prevent double-click submits.
Rules and deadlines differ by region and acquirer — always check the instructions in your PSP dashboard.