Contract finished and still being debited, no response from staff

My contract expired in June and I did not want to renew. I have been paying for two years R269.00 per month and moved just after I took out the contract. There is no coverage in my area in the Western Cape but I still kept paying and cancelled when the contract expired. Cell C is still debiting my account although I have given them the reference numbers for the cancellation, I have phoned numerous times and spoken to Nanikhozi, Tato and Roxanne and no one gets back to you with an answer. Their service doesn't exist, they never return calls although they promise they will. I am fed up with having to repeat my experience to every person I speak to and nothing gets done about it. The supervisors are continually in meetings and unavailable to help so where does one go from here? No one seems to care...........never again Cell C!