Account settled in full.

I made a loan last year by FNB to settle account with MFC.I was given a discounted amount by MFC which FNB settled and I still received all the necessary paperwork from MFC regarding the settlement.They also sent a settlement letter via email but I still received a notice of payment afterward and contacted them regarding it.I was reassured that the matter would be handled.I then ignored any other notices that followed every month after that, thinking it might be a computer error that they didn't fix yet.I received a letter for a second month which stated I owed them over R5000 still and that it's accumulating interest.I contacted them several times and recently my wife phoned and was given a number of the manager(Thembi) to call but the phone never gets answered.I contacted them on Friday and after I asked to speak to the manager,I was put on hold and then the call went back to the front desk.I asked the lady to put me through to that section again and spoke to a Percy.I insisted to speak to the manager but he had me confirm all my details first and I had to explain everything to him again.I asked to speak to the manager I was put on hold for over 30mins and then my airtime was up.