Absa bank is a scheme

After realizing that Absa is charging me way more than what we have agreed on monthly , I had decided to change banks. Now upon going there a few times trying to close my cheque and credit account. I was advised that I have a balance of R 348.92 but the consultant could not tell me exactly where it comes from. This is after I have paid the balance that was showing on my banking app. After a couple of minutes waiting for the consultant to tell me where the balance comes from, I got tired of waiting and just decided to pay the balance. I was then told that I need to call the credit card department in order to close my credit card. I called them and after they tried to convince me that I should keep the account open, I was again told that I have a balance of R 257.38 on the credit card which I need to pay before I can close the credit card. and then again I did not get a clear answer of where the amount comes from, I was told its interest coming from December 2020 and my question was its Feb 2021 now how is that an interest from December is only being charged now? Also why is the balance not showing on my app? I have now decided that I will not pay this credit card balance until someone explains it to me where it comes from and why it is not showing on my app. I thought when you settle your account you get a discount but it seems you get interest from Absa. Please call me urgently and give me proof of where the balance is coming from as I would like to close my account asap.