BAD SERVICE !!!! No communication !!!!!

I have cancelled the contract that didn't want and they cancelled it but Vodacom still keep on deducting money out my account ,if you phone the call Centre you cannot get assistance at all ,I am still waiting for them to phone me back to arrange my refund and this is going on since September .....This is bad !!!! Very Bad from Vodacom i need to constantly phone them and they just don't care about their customers it was promised that they will not deduct anymore but they did and they collected 3months payment but I don't use their unit ....I need Help!!!!! please ????????........