Telkom refuses to cancel my contract on time yet they admit the it’s their fault.

My contract ended in December 2021 so I was on a month to month thereafter. I called in on 24 January 2022 to cancel when then agent told me that the last debit order will have to be in February since it’s too late however I received an invoice on 4 March 2022 saying that I will still be debited on 25 March. When I called in the agent says that t it has still not been cancelled but she can see the communication and also admits that the fault lies with them but there is nothing she can do to stop the debit order. I will not tolerate this so please use the call recordings and cancel ASAP as I will not allow my credibility to be messed up due to insufficient funds.