Unable to close account

On the 11 Dec I phone standard bank to find out how much I owe on my revolving loan account. I was told it was 1721.67 which I paid on the same day. I then went to the Gugulethu branch on the 15 Dec to closed this account, as I cannot close it by calling the call center. When I got there, i was told by the consultant to pay a 90.03 as interest, which I did. I then phoned on the 21 Dec to confirm if the account has been closed, just to find the account is open and I'm owing another R90. For what? The consultant at the call center referred me to the branch again, spoke to Vuyolwethu who informed me the system keeps on re generating interest on the account. She will reverse and close the account. Phoned again 22 Dec to see if the account has been corrected and closed. Still open and I'm still owing. I need this account closed ASAP!!!!