If the landlord is not blacklisted within the time limit, the situation is not serious and the arrears have been paid off, then you can call the bank's manual customer service to explain the situation. The general bank staff will unfreeze the landlord again and do not need to apply for a credit card again.
It is suggested that the landlord communicate with the human resources customer service of the bank first to confirm his own situation, and then see whether to unfreeze it or wait a few years before applying for a credit card.