Standard Bank CANNOT CLOSE ACCOUNT

Good day i have been thrice to the Standard bank branch to close a student account which i haven't used for more than 10 years. the bank tells me that there is an outstanding balance, which i then settle. even after settling the amount the bank adviser says she is unable to close the account for some unknown reason. she then tells me on the 23 Oct 2018 that it should take 2 to 3 days for the account to be closed. it is now the 30 Oct 2018 and still i see the account on my banking app. This is really frustrating as i have done everything on my side and this bank cannot even close the account.