3 months after contract cancelled and still paying

My cell phone contract was supposed to expire on 13 August 2015. Early in July I contacted customer care and said I do not want to continue with the contract. I was told it would be cancelled. End of August after my debit order went through I contacted them again and again I was ensured it is cancelled. End of September my bank account was debited again and I was told the billing works one month in arrears and everything was finalized and I would not have to pay anything else. Now end of October my bank account was debited yet again and on calling customer care I was told the contract is still active and if I cannot provide a reference number regarding my previous queries there is nothing that can be done. i was never given any reference numbers when I spoke to customer care previously and I didn't know I was suppose to ask for one. This is poor customer care to say the least and every time I have to phone it costs me a lot of money as it takes forever to explain to whoever is helping me what is wrong etc. My last call this morning cost just over R24.00 and still I don't know if my problem is resolved and I would like to know about the extra money I paid so far.