Cancellation of Contract

I cancelled my wifi contract in January. I received a call a few days later ( still in January) to confirm my cancellation. It was agreed that all services will be cancelled from the 1st of February and that my last payment will be at the end of Jan including an R800 cancellation. From the 1st of Feb I had no wifi service. However I was extremely angry when I was debited an amount of R1520 on the 28th of February. I did a reverse transaction as I was told that there will be no payment for February. On the 15 /03/2019 I was debited an amount of R 758 When I phoned Telkom I was told that the main sim was not cancelled and that I still have to pay for it even though i did not use it and I would also have to pay a penalty. Today the 16/03/2019 I was debited an amount of R 2276.I need someone to explain why I’m being debited for so many different amounts. I also need to know why Telkom is penalizing me because they did not process the cancellation correctly! Any amounts deducted after that is tantamount to theft and I will not tolerate this. Until someone explains to me what I’m being charged for, I will not pay any further amounts.