Keep on taking money out of my bank!

Since November 2018 we have been trying to stop a debit order on a cancelled contract. We have sent numerous emails to cell c but they just keep deducting funds from our account. I am so frustrated at the moment! They just don't give any service! In my most recent attempt I phoned and emailed Nomkhosi Buthelezi all the proof that the contract was cancelled and still no feedback apart from "I have sent it to customer care." This is unacceptable!