Online Fraud

I got a call from a person claiming to be from a bank and asked for my bank details. He took my OTP three times and did three transactions, of which I never received any message from the bank. But after the call, just to be on the safer side, I checked my statement and three transactions showed using all my money in the account. I immediately called my bank and asked for the details of the transaction. They gave me the transaction details and it showed that three recharges were done on Vodafone mobile. I immediately called the Vodafone officer to notify of the situation so that they could revoke those three transactions. I then lodged a formal police complaint at my nearest police station giving them all these details. The police officer casually said that they are unable to track the culprit and they can not ask the merchant(Vodafone) to revoke these transactions. What should I do in this case? Please help as I have read that if properly dealt with, I can force the merchant(Vodafone) to revoke these transactions.