Bad service from Telkom

Hi My name is Juan Pierre Jacobs and I have an issue with Telkom. I had a contract with them which I paid for and canceled once the contract was finished. They are now sending invoices for payments and I have contacted them numerous times advising them that I canceled all contracts with them. I also asked them what the amount was for on the invoice and they advise me that it is for data being sent to me every month but I do not receive any data or airtime from them as I have canceled the contract and I informed them of this. The cancelation was done over the phone with them so I do not have access to this but the do record the lines but they insist that they are still sending data to me. Can someone please assist me with this as the amount is for R83 every month and has now come up to an amount of R1400 which I do not have. I have not been using their service for the past 2-3 years now and don't see why I should be paying for something I am not using. Any assistance would be appreciated.