Poor Service - once again - no surprise

I am struggling since October 2015 to cancel one of my contracts that reach maturity. They keep on billing me a ridiculous amount for data I don't use. I phoned last week and was promised everything was sorted and that the cancellations department will phone me. They did phone but the call dropped and just never bothered to phone back. I tried to phone the number but it was constantly engaged. I phoned the call centre this morning just to hear the line is still active and the same old story of we will forward the query to the cancellations department to assist. O my goodness | give up, what more must I do. I even lodge a second case in January 2016 (case number ***3) but still just nothing is being done about it. The best is they try to reach me on a very old Vodacom number, my goodness can they not trace my Telkom mobile number. I will get a response stating we have tried to reach you on that Vodacom number with no success, then further to that they will try my daughter on her expired Cell C number (also Telkom), don't ask me where the hell they got these contact numbers from, it's ridiculous. There is one store that stood out but they can do only so much - Mall@Reds