MTN double debits then suspends my account

So I've been with mtn for 30 years and this last upgrade has given me a lot of trouble. Double debiting my account. Suspending my account saying it's in arrears. I've been there twice and every month on the phone with them and this month I had to reverse the second unauthorised debit order. I showed them my bank statements and they didn't want to take a look at it. They say the system says it's in arrears. The mtn app does not record the correct information and they send messages every time that I'm in arrears but my bank statements says otherwise. The say every month that ive been credited with 5 gigs data when in fact its only 3 gigs. Nothing adds up. Bank chargers. They told me I owe them 1500 I paid it thinking I'm in arrears but I wasn't. They owe me money. Today they suspended my account saying I owe them R52 which I don't owe and I can't make arrangements cause its passed 90 days. I was told in the past that I must ignore these messages as my account is up to date. You can't get a hold of the manager even when you go into the branch. I'm frustrated cause according to them their system is not wrong. The mtn app now does not work with my wifi you need an mtn router for that. What nonsense is that. When I paid 1500 it still said I paid 1290 it's not the correct information. I don't know if my account is being debited by an separate party,cause apparently they can't see that my account is being double debited. What can I do as they don't even want to look at my bank statements. How can tou go in arrears when you have a debit order in place Can?Can I go consult a lawyer? and they can investigate and I know mtn owes me. Please give me advice!