Vodacom cellphone contract ****!!!

I was on a cellphone contract with vodacom which ended in September, I have been trying to cancel it since then with no avail. Went to the store in Hatfield and they said they can't help i need to call the number for cancelation which I have been doing since. I keep getting sms and emails from them confirming they have received my cancelation request and the call ends. It's bad enough that they have a ****py network now I have to run after them to cancel a contract that ended in September already worse part they are deducting an even larger amount then the initial contract agreement. Whatever you do , do not take a contract out with these ******!!