UNFAIR and exploitation of customers by FNB and MBD

I was paying my cheque account for several months and a consultant would call every month to offer me a settlement amount. In July when the MBD call a consultant offered me the settlement which I took and the consultant advised me that the call is recorded, I then paid the last amount owing on my account which was R6050 & R15. I waited for the settlement letter till today, MBD has been sending correspondence that I owe FNB R2700, I forwarded MBD the proof of my last payment and they ignored me and they keep on calling and sending me meassages that i must pay the accont which is paid up .Kindly assist to resolved the matter. L Matlala