What happens if a card on file has expired and the studio wants to complete a refund to the expired card that was used to pay the invoice?
It is up to the issuing bank if the refund can be completed back to the expired card. If the refund attempt declines, then they have not allowed it. Typically, they will allow it as long as the account is still open and won't if it's closed.
NOTE: Even if a new card is added to the client profile, the refund will not go to that card after selecting to refund back to card (has to be the original card).
What are the best alternative options?
The studio can choose to process a refund back as cash, check or credit balance.