BAD SERVICE

I requested for an early termination of the contract with MTN in June and paid the early termination fee but the matter is still not settled. I still get invoices and I have been speaking to the agents but no one is assisting me. The last person i spoke to was Kgosigo from the retentions department who advised that he will get back to me in 48hours but he still has not responded to me. Everyone is taking me from pillar to post but cannot assist me