Incorrect Billing, account handed to Legal

I have been receiving higher bills from MTN towards mid year and queried it. After calling the Call centre, I was advised that the additional user/number on my contract ***, has apparently been accessing more data than normal. I was highly unsatisfied as I was not aware that this could be done, but paid the higher acount regardless. This continued to happen and I was forced to call MTN again in August to request a break down and explaination as to why this was not revoked as was promised to happen before.I have been a loyal contract client with MTN since 1997 and was not even aware that this could be done by an added user. Instead of the breakdown I requested or feedback, more increased bills arrived and after the added user confirmed that no extra data was being purchased, I once again requested astronomically high bills of approx R2000 for the month of Oct. I called in Novemeber to once again query this and again requested a breakdown. I have received nothing to date. I was also advised in Nov that I am in the legal dept, contacted them and enquired how long it took for MTN to send account to legal and was advised 3 months. I disputed that I was 3 months in arrears.