Answer:
You can reverse provisional credit upon receipt of a merchant credit, deny the consumer claim (due to the merchant credit) and declare the claim closed.
But if you have already made a provisional credit final before the merchant credit is credited, you cannot reclaim the provision credit. Final means final. You can let the cardholder know that he's been paid twice and suggest the cardholder refund the funds to the bank, but you cannot demand it and you can't take the funds without the customer's permission.