Telkom steeling money after contract cancellation

Last year 2017 I had a dispute with Telkom about my contract being cancelled. I ran 24 to 25 months and paid every month and then sent through a cancellation of the Telkom contract but Telkom said I sent it to the wrong cancellation department because I sent the cancellation to fixed lines instead of mobile lines or some ridiculous story like that. Telkom then started taking extra money out my bank saying that the contract is not cancelled. I sent the cancellation to the email on the cancellation form but they say it was the wrong email (there are two emails on the cancellation form I later realized) The worst thing is they charging me for data that I never used because after cancelling the contract I threw that sim card away and never used it again but they are charging me for a 26th, 27th and 28th payment for a 24 month contract which I cancelled on the 24th month and I paid an extra 25th month just to make sure it was properly cleared.