Vodacom Cancelation/ Upgrade

I have cancelled a contract 7 times as I was **** to regarding the terms of what was actually happening. The sales people will say anything to get the sale which actually saves me money, but now I am unable to upgrade my device as it counts as an upgrade. It's an absolute Joke every month I call in cancel it they say on the 1st of the next month I can upgrade and then the same thing happens. I am trying to give Vodacom more business but they are to useless to realise this. I got hold of a manager ishmael matshotyana, who I don't believe has worked a day in his life, I have sent him 10 emails with only 1 response in a month to say someone will call you shortly, which nobody did. He is getting paid to do nothing. I need this to be sorted out!