Switching processors stops future transactions from flowing through the old account, but it does not erase the transaction history attached to that account. A customer may dispute a purchase weeks or months after the original sale, which means the old processor, old MID, old transaction records, and old evidence can...
How to Time a Payment Processor Switch Around Open Batches, Deposits, Refunds, and Disputes
A processor switch can appear successful because the first transaction works on the new terminal, yet the merchant may still have an open batch at the old processor, a pending ACH deposit, an unsettled refund, an active dispute, or a reserve adjustment waiting to post. Turning off the old environment...