MTN CONTRACT

I have 2 contracts with mtn from May this year. Someone added a new contract with my details without my knowledge and approval, I received the phone and took it back because I didn't apply for it. Extra money was debited in my account from May until August when they debited huge amount of money which I reversed. I have been calling making follow ups with my account from may till now they even blocked my services with 2 contracts that I know which I made sure that I deposited their balances and they sent an sms saying I will be blacklisted My alternative numbers are *** if you reply via call or sms Can you help me with this issue Thanks in advance