Pavel acquired a credit card in 1998 and made the necessary repayments on the card every month until October 2012, when he accidentally underpaid the amount by €19.
He called the lender in November to say that he would make the payment of €19 as well as the late fee charge of €15.
But following the missed payment, the lender said the account had fallen into arrears and it placed a restriction on its use on October 30 - but failed to tell the customer of this block. He was therefore shocked when his card was declined in a shop and was then told by the lender that the card had been withdrawn and would not be reinstated.
Pavel told the Ombudsman that the balance on his credit card when it was blocked stood at €14,166. He has paid €15,250 towards the outstanding balance, but as €9,000 of that amount being interest, the balance has only reduced by €6,250.
Pavel complained that the lender had unreasonably blocked his account as a result of a small underpayment, that the lender charged a very high interest rate after the card was blocked and that it dealt with him in an unacceptable manner.
The lender said it had sent a letter to Pavel to tell him the credit card account was in arrears, but Pavel said he never received the letter and the lender did not provide a copy of the letter in evidence submitted to the Ombudsman.
The Ombudsman said it found that the lender's failure to fully maintain its records breached the Consumer Protection Code 2012 and it also noted that the lender did not comply with the Consumer Credit Act 1995 by clearly stating what was needed to remedy the situation.
He said that while the lender was entitled to block the customer's credit card, it was disproportionate and unreasonable when the underpayment was just €19 and there was no evidence of previous arrears.
According to the Ombudsman, the lender also failed to comply with European Communities (Payment Services) Regulations 2009 by not unblocking the credit card once it was paid off.
But the Ombudsman also found that although the lender's decision to block Pavel's credit card was unreasonable, it was entitled - due to its terms and conditions - to charge the same interest on the account when it was blocked as when it was active.
He also concluded there was no intentional wrongdoing by the lender when Pavel complained that he had to wait for 25 minutes on hold to talk to the lender, and that he had found no evidence that the lender had dealt with Pavel in an unacceptable manner.
The Ombudsman said he had substantially upheld Pavel's complaint and directed the lender to pay €10,000 in compensation. He also told the lender to remove any adverse reports on the customer's Irish Credit Bureau record.