contract cancellation

<p>I had a contract with Mtn and settled it 29/09/2015 and asked that they cancel the contract as i will no longer use their number i even got rid of the simcard. Few months later someone from Mtn calls saying i owe Mtn R523 and i told the person that i settled the account and sent proof of payment to their customer care e-mail and the person said to me if cancelled the contract then it means somebody from their side open the account without my knowledge. After a while i called i Transunion to check my credit score and everything was fine Mtn updated that my account has been paid up but failed to remove the balance. Now i am in a process of buying a house and they say there is an outstanding amount on my Mtn account and that i should get a letter from Mtn stating that it is settled. I have been trying to call Mtn but nobody answers it is a nightmare and can someone from Mtn please get in touch because i need that letter.</p>