Unauthorised billing of Account

Hi all, I am not even a customer of MTN, yet last month I was debited R4100 which I thought was a mistake so I took my time and incurred costs in reversing the transaction which also had overlapped into my overdraft. I think it probably would take years and cost even more to retrieve these costs and why should we because the fault lies with MTN. Today I was debited again for the amount of R4600, which again I had to reverse. I could get no answers from my bank but to find out from Mtn why are they debiting an account thats reversing the transaction. I knew this is going to be failed quest but I still wanted to follow up and correct the problem so it will not happen again. I remained on hold from 9:10 am to 10:20 am this morning to get help, but finally ended the call. I am trying a landline number for the last 2 hours but is busy. Do these companies feel they are grown so big they dnt have to worry about the smaller people or in this case I am not even 1 of their people but is getting billed like 20 peoples contracts. Hope this helps and I get some response because this is unacceptable from a \service provider"more like a \""problem provider\"" I will end up with all the extra costs."""