Hmm. I'm not convinced the bank are right. You have a contract with the hotel. The bank are party to this contract. You've cancelled the contract and are due a refund under the contract. I know a UK bank refunded a credit card in a similar situation where there was partial delivery on a contract, because they had to under the UK Consumer Credit Act. I assumed the Irish legislation was similar.
I would ask the bank for the necessary dispute form just so you can submit it in within the 90 day period, even if they claim they won't pay out. You should also check what their nofication period is -- it turns out for some (or perhaps all) banks you have to report it within 60 days, which would mean you are too late.