Invoiced for a contract that has been closed

31 August cancelled contract and telkom never cancelled it. So it went over into October and being a nice person I allowed it. Spoke to a lady on 6 October who promised it will be cancelled 31october. It's the End November and contract is cancelled and the number has been moved over to prepaid but still being invoiced. Phone every second day and have been to the store countless times and no one has returned my call or sorted out the incorrect billing. I have been left with no choice but to contact the consumer protection act and put legal steps in place. I have even been forced to place a stop order to prevent any further charges which was at my own expense as well! *********** and useless service provider! The one woman couldn't even read the invoice and told me I loaded the contract with prepaid airtime!