1026.13 (a) Definition of billing error. For purposes of this section, the term billing error means:
(3) A reflection on or with a periodic statement of an extension of credit for property or services not accepted by the consumer or the consumer's designee, or not delivered to the consumer or the consumer's designee as agreed.
The consumer never received delivery of the services (the international trip).
I agree that this is a billing error provided that the consumer submitted the claim in writing. The fact that the trip is non-refundable is a red herring. (Note if the customer's dispute was that they wanted to cancel the trip after booking and couldn't because the trip was non-refundable, that's a horse dispute of a different color!)
If possible, the Bank should file a chargeback via VISA/MC using the "Services not rendered" chargeback reason in an attempt to recover the funds from the defunct merchant (or their sponsoring bank).
_________________________
Sola Gratia, Sola Fides, Sola Scriptura, Solus Christus, Soli Deo Gloria!
www.tcaregs.com