Continuous chase up by SBI cards for payment of Illegitimate/fraudulent credit card bill

There were 4 fraudulent txns online on my subject credit card, for which no OTP etc were shared by me, and txns not done by me. But despite alarming SBI cards the same day over their site/helpline/ and also by mail about the fraud., they didnot take any action and allowed the txn to settle. Further, while the txns were initially showing as done to merchant A on 27/8/20, but while the settlement came, it was showing as billed to mercahnt B on 26/8/20; i.e. settlement of bill was done one day earlier and also to different merchant. Despite f/up with SBI cards, till date they didnot settle the dispute, but only raised the bill with escalated amounts of penal charges every passing month/day. They are creating innumerous ways of pressure tactics to pay up. I raised the matter to RBI, but till date nothing happened. Pl advise what to do.