MTN_A|_s Poor Customer Service!

I settle my contract earlier this year - settling the closing balance on my last statement received. 6 Months down the line I am sent a statement with outstanding payments and to make matter even worse I am now being sent an email with regards to changes being made by MTN pertaining my CPB Credit Bureau Profile which most certainly is not a good thing! I understand that in the T and C's of the contract it states that a request in the form of a letter should be sent to MTN stating that you as the customer no longer wants to continue his/her contract with MTN in order for them to terminate the contract(I was only advised this today -14.07.2015 by a MTN representative). With that being said, if I was told to draw up a letter initially stating that I do not wish to continue my contract with MTN then I would have done so immediately after paying the closing balance however in this instance I was told absolutely nothing with regards to that. I have come to a conclusion, not to pursue this but to settle the \new closing balance of R1049.94"the end of this month and the sole reason for doing this is because I don't want anything to do with MTN ever again for their poor customer service!!!"""