Unauthorised MTN Debit Order with no resolution after 3 months of Debit Orders

My Husband received a shock unauthorised MTN debit order off his personal bank account 03rd May 2022. He does not even have any MTN contract at all. For months now he has been trying to get MTN to sort it out, even having to send them a affidavit certified at the police station & other documentation. MTN confirmed that it was an online contract sign up with all my husbands details & that they have sent to the ***** department & were told it could take 21 business days to resolve the matter. With constant back & forth with MTN his account was debited again 01st June including the May'22 amount which he reversed through the bank & again now 01st July now including May & June debit orders he had reversed due to being unauthorised debit orders. Therefore the amounts keep doubling then tripling and so on. My husband does not use this bank account & therefore only pays in enough money each month to cover 3 very important debit orders (incl Life Insurance). Therefore these unauthorised debit orders cause his bank account to go into overdraft which it has never done so in his history. This in turn can cause an issue with his existing 'excellent' credit rating. On top of that, it caused unnecessary bank charges due to disputing the debit order as well as putting it in overdraft. MTN do not seem to be taking this seriously, since already 3 months of unauthorised debit orders & each time he emails, he receives an auto responses saying he will receive a response with in 24 business hours, but weeks later still not receiving a response. 21 business days to resolve this from the beginning of the issue is already over 10 weeks with still not resolution.