Cancelled contract useless accounts department

I have cancelled my contract with Vodacom , due to the high fees.<br> I have change over to pay as you go, what a disaster.<br> First I still get charge additional charges that no one can explain <br> 2nd I can not use the internet at all<br> <br> I phone the call centre what useless staff, they cant understand a simple question.<br> What must you do to stop all this additional charges and get the phone to work