MTN billing me for cancelled contract

I have logged several calls and sent several emails to MTN service centre to cancel my contract after 2 years but still nothing has been done and I am still being charged for their services. The service from MTN is pathetic as this has been going on since October 2015. I have given them 2 months notice but now 2 months after the contract had been cancelled on anniversary, I am still being charged. Since Nashua mobile is no longer handling my MTN account, the service is non existant. I would like MTN to contact me as nobody has sorted this out after several emails and calls. The call center number most of the times does not even work. Very glad I moved my other line to Vodacom as this service is unacceptable and a waste of my time!!!!