How do you cancel MTN Contract?

Ok, so I emailed [Email Removed] on the 05/08/2015 to ask them to cancel my cellphone contract. Asked them to contact me and they never did. I resent my email on 12/08/2015, and phoned the call centre. I spoke to a lady called LINDIWE who said someone would call me. Guess what, I am still waiting. I have even tweeted 3 times to @MTNza, and there has been no communication with me regarding my contract I want cancelled. I have emailed them again, and will call and tweet - but really? Is this how you go about cancelling a contract. The service is absolutely disgusting. Never mind the network problems which is what made me cancel... I was with them for years, and never had problems - and now this! I AM STILL WAITING FOR SOMEONE TO ACKNOWLEDGE I WANT MY CONTRACT CANCELLED! PLEASE CONTACT ME!