The initial claim would help indicate more, but assuming it was the authorized user who abused their authority with the device and has triggered the claim of unauthorized use, Reg E definitions clear this up:
(m) “Unauthorized electronic fund transfer” means an electronic fund transfer from a consumer's account initiated by a person other than the consumer without actual authority to initiate the transfer and from which the consumer receives no benefit. The term does not include an electronic fund transfer initiated:
(1) By a person who was furnished the access device to the consumer's account by the consumer, unless the consumer has notified the financial institution that transfers by that person are no longer authorized;
https://www.bankersonline.com/regulations/12-1005-002
If neither the customer nor the authorized user made the charges in question, there could still be a valid claim.