Vodacom refusing to cancel my contract.

I had multiple contracts with Vodacom, they were active for many years. Just recently I was due for an upgrade in AUGUST and on the day of my upgrade I cancelled some contracts that I did not need. I called the call centre and went through the procedure of cancellations, even received smses CONFIRMING MY CANCELLATIONS. What IRRITATES ME is that I am still being billed for these CANCELLED contracts. I have been calling the call centre and I received the same sms every time. They are deducting amounts I did not sign for or agree on. This is very much inconvenient to my monthly finances. This needs to come to an end.