unauthorised transcations

i have been having unauthorized transactions going through my account for the past 2 months it was reported the first time and it was resolved and the first card was cancelled. the following month the same thing happened and on the cancelled card the money that was reversed to me was again debited on my old cancelled card. now the same issue with unauthorized transactions happen again now my account its currently sitting on -R7600 and am getting calls from fnb to make payments. i filled the the disputes forms again around the 1 st of november there was no communication or update after that. am still waiting even now for communication. i opened another checque account using my internet banking cause i couldnt use the account sitting on -7600. Can i please get help with regards to that as i need this to be resolved as soon as possible. this is really becoming a problem to me please assist am begging as customer.