I demand immediate contract cancellation

I am now at my wits end with the time it has taken them to cancel my contract. The 2 year period ended on 31 October 2015 and its taken me half a month whilst requesting contract cancellation. <br> <br> The call centre agents hide behind the retentions and escalations department who have emailed a request for me not to cancel after I have made it very clear that I want nothing more to do with them. I have yet to receive so much as a response.<br> <br> This has not even been the first of many troubles endured during the 2 years of this contract. They made it so miserable that I could not wait to get out. For this reason I have dissuaded many of my loved ones from entering into an MTN contract and will continue to do so. <br> <br> I have been as nice as possible under the circumstances however I have run out of patience. Even this very minute I have neither been migrated to prepaid nor received their promised sms confirmation.<br> <br> Because I no longer trust them, I will accept nothing less than an emailed letter confirming the end of this contract.