The bank won't overcharge. It's just possible that your card has been swiped and you don't know it, that is, there are some transactions in the bill that you didn't generate. You can ask for a bill to check, but it costs money and it will take about a week to get the result.

This is how credit cards are calculated. If you don't pay back the money in full on the last repayment date, you will get interest of .5 ‰ of the interest from the day you swipe the card, that is, if you pay back one point less, there will be a lot of interest (but there will be no interest if you pay back 1 yuan less from September 1st), and if you don't even get the minimum repayment on the last repayment date, you will still get 1% of the unpaid interest, the lowest 1 yuan.

In this way, you will naturally owe more money. Personally, I suggest that you return the card as soon as possible or pay attention to the bill and repayment time to avoid similar situations.

also, there is no interest if you pay back at 9: pm on the third day after the final repayment date.

the penalty reminder service is to remind you that you have not paid back the money by SMS two days before your final repayment date. With this service, you only need to open it yourself, and you need to charge 3 yuan a monthly function fee.