Why did you send me a short message saying that the available balance has been paid off after repayment with overdraft card of CCB?

If your CCB credit card is repaid, the bank will tell you whether the current bill needs to be repaid. However, even if this period is not repaid, it does not mean that the available line is equal to the credit line. Give you an example to understand better.

Suppose your credit card limit is 10000, your bill payable on June 7th is 5000, you spend 3000 on June 10 and repay 5000 on June 15, then the bank will remind you that the bill has been paid off, but your available limit is 70000, because there will be 30000 in your bill in the future.