It is the CC issuer (bank for this purpose) problem. There is no reason why a bank cannot release a hold within one business day of the merchant vendor's action. Amex and Chase, as others note, typically do not take more than that one day.

OP's problem may be related to where the charge is authorized (USA ?) and the hold placed (Ireland ?).

Starting point is the CC issuer / bank. Barring that, it is having CL to handle transactions.