Outstanding complaint since December 2021/bad service

Please advise why there is still amount due on my account? The last confirmation was to pay R1437 which went of my account plus another R700 which should cover the 4g Sim card. The account has been cancelled in December and confirmed by Nobuhle that it will only be billed till end of January, please explain the outstanding amount as the account has been billed for February and I didn't use your service