No help from FNB

In 2016 I opened a cheque account with FNB, I later changed my mind and requested that the account be closed telephonically. I did not collect the bank card. Unfortunately the account was not closed and accrued charges. I then deposited money into that account for charges and the money bounced back into my account as the FNB account was inactive/closed. I did not hear anything from FNB since. Fast forward to 2020 when a bond originator was requesting a home loan on behalf, I then receive a decline letter from Fnb citing that I had bad conduct on residual loan. Upon enquiry I was told it's because of the cheque account charges that were written off and that the account is with their legal department. I have been sent from pillar to post and nobody is able to help me. I even initiated a process online however I'm still waiting for a response. I'm getting frustrated with the process because no one is able to advise me on how to resolve the issue.