1. If you really didn't activate it yourself, you just need to explain the situation to the bank, and the bank will conduct a follow-up investigation and reply to your processing results.
2. If it is true and you just forget it, then pay off the arrears as soon as possible and cancel the card, so as not to affect your credit history.
3. If there is not much arrears and you are not sure whether it is true or false, you can cancel the card after paying off the arrears in order to avoid wasting energy. If you don't find the result after a long delay, your credit rating will drop.