Cancellation of Contract - takes a year

I am highly disappointed in the lack of customer service received from cell c. I tried to cancel my contact in December 2020, and I was informed I would only be able to cancel it in the February of 2021. So I waited until the end of Feb, and then attempted to cancel the contact again. I was told that I would need to send a written cancelation of contact letter in, which was done but still after numerous emails and phone calls - a year later I still have cell c taking debit orders off of my account - please note this sim has not been in use for a year now.

please could someone that knows what they doing and able to assist contact regarding this situation. I am 72 years old and cannot afford these extra expenses or the constant trips to the bank to stop these orders, as the amounts keep changing to get them through.