Still no feedback on ending my contract!!!!!

It has been a month since I changed my tablet contract to Prepaid and still have not heard anything. I know for a fact that you useless people will still debit my account yet you give no service. it is ******** that you can take my money for not doing what you are supposed to do. this has been escalated 3 times and I still receive no feedback. I will return your debit orders and you can then call me and sort your **** out. Also I have been waiting since 1 April 2015 to upgrade my cellphone to a phone that you have been advertising for 2 months but apparently you do not have stock!! MTN is the worst company I have ever dealt with. I will be cancelling all my contracts with you.