MTN unauthorised debits from my bank account.

Since the 15th February 2022 MTN has taken unauthorsied debits from my bank account each month in the amounts of R 3950, R 7468 and R 10 985. I have written to the MTN ***** Department five times and the MTN Complaints department. I have had no response from MTN ***** or MTN Complaints. Surely this type of behaviour totally *********.