First of all, we should understand a concept. You are not talking about a credit card, but a debit card. Simply put, a debit card is a savings card. You can deposit money first and then withdraw it. Credit cards are debit cards, so there is no money to overdraw.

To determine which card is the repayment card, you can take the following methods:

1. Find the loan contract. The loan contract includes the card number and a copy of the repayment card. Just check the card number.

2. Go to the inquiry machine of CCB or online banking (if enabled) to inquire about the transaction details of each card. Generally, the bank will automatically deduct the loan amount that you should repay every month on the 20th of each month.

Just go to the CCB counter and ask the teller to check it for you (I brought some cards).