Recently, we signed a contract with Fiserv to manage all debit card dispute filings. In one instance, a dispute was filed for charges under $50. Fiserv automatically credited the customer's account and sent a final notice indicating that the case was closed.
The Deposit Operations Manager approached me with a question: What happens if a customer files a dispute, Fiserv credits the account and sends the final notice, and then the merchant issues a credit to the customer's account a few days later? I explained that once the final notice is sent, there is nothing further that can be done from our end. We also wouldn’t be aware if or when a merchant would refund the customer.
The manager then inquired if we could deduct the amount from the customer's account if they received a credit from the merchant after the initial credit and final notice were issued.

Just need some advisement.

Thank you!!