Standard bank

Hello Peter In 2018 I took out a loan with Standard Bank and paid it up before the loan term. I even received a paid up letter from the branch in Richards Bay. In October 2020 I went to MTN to get a cellphone contract but my deal was not approved because of "unsettled account". I logged in to my clear score and saw that the loan was still active. I went to the branch to query about this they were also not sure what happened. On the 5th of November I received an sms saying the query has been resolved. Today 09/12. I'm at the branch again to follow up and the telling me that the account is still not closed because of amount outstanding. My question is where was that communicated with as the client I bank with them, my salary goes in the Standard bank account why have they not debited the amount due Why did they give me a paid up letter if the account was still owing. This has ruined my credit score