Cell C failed to cancel contract for pensioner

My mother has been trying to cancel her data contract since November as she is a pensioner and can no longer afford and she no longer needs the data contract. After numerous attempts to call, you either get message that says something has gone wrong or the call gets cut, we eventually to send a mail. After a week they finally tried to contact her but the she missed the call and we then phoned them back. When the lady answered the call I explicitly told her that my mother wants to cancel the data contract. This was on the 31st of December 2022 and when my mother spoke to the person she again stated that she wants to cancel the contract. My wife and I was sitting next to her and heard the entire conversation. When she received het updated contract on the 6th of January the data contract was still shown and she was now going to pay more. We sent a mail the 7th of January 2023 stating that they need to listen to call and cancel the contract immediately. We received a Case Number : *** but no action was taken and they debited my mothers account.