MTN ******** DEBIT ORDER

On Friday, 24 Aug 2018 discovered an unauthorised debit order activated by MTN on my Bank account. Went to local MTN store to cancel. Staff member lodged a complaint. I had to go to my bank, get a statement and affidavit verifying my account and certified ID. Handed it in and lodged complaint Monday, 27 Aug. On 1 Sept 2018 ANOTHER unauthorised debit on my account. Lodged complaint through MTN shop on Monday 3 Sept. After a week MTN had not responded to complaint of 27 Aug. I lodged a complain online on 3 Sept giving 24 hour ultimatum. Today, 5 Sept, no response even! Can someone help?