Consumer Redressal

I have an account od SBI-Credit card, which was not used amsot 2 years. From last 1 year suddenly I get an bill of Rs.2000+ for purchasing insurence through this card. But that was not done by me. When I go for closing that card by pay that amount , that payment was not made as i not use that card through long time, and every month that amount gradually incresed. After lots of mail correspondence with SBI-credit card dept , they wave out the cost of insurence charges, but bill still came for the fine of that amount late fee charges of Rs.900/-. now that is also gradually increasing. Please help by giving suggestion how to close this chapter.