The credit card companies are quite often very good about that. I received a gift card, and at some point, checked the balance and it seemed like 50 or 60 bucks had been spent and I didn't remember it. I wasn't positive it wasn't me, but I didn't remember it---wrote Mastercard, and they, without questioning (although if they showed proper receipts it would have immediately answered whether it was more or not) and they sent me a new gift card, full value.
My wife uses Amex for some things and they notified here about an unsual charge. Turned out it was fraud for a few thousand dollars, Amex made good on it and immediately sent a new card. Without knowing the circumstances of the OP's issue, I can't say anything, but often, even banks are helpful. I once sent a rent check, apparently stolen out of a mailbox and the payee changed to a different person, and Apple Bank made good on it. (That is stolen out of a NYC mailbox, not the landlord's mailbox). The woman at the bank told me that criminals had been known to steal entire mailboxes and change any check payees in there to something else.