Accounts not closed as promised.

As per settlement campaign from LGR Incorporated I have made a settlement payment into my Standard Bank account. The settlement campaign gave discount on the outstanding balance on the account. I was issued a letter as full and final settlement of the account. It seems that the account was never closed and that the remaining balance was turned over to MBD Inc for collection whom is phoning and emailing me know even though the account has been settled in full. This is very frustrating as I have paid the amount as stated on the settlement letter and was promised that after payment that the account would be closed automatically.