Banks must provide customers with 24x7 access through multiple channels (at a minimum, via website, phone banking, SMS, IVR, a dedicated toll-free helpline, reporting to home branch, etc.) for reporting fraudulent transactions that have taken place and/or loss or theft of payment instrument such as card, etc. Unauthorised transactions resulting in erroneous debits to customers accounts/cards, the Reserve Bank of India, in a draft circular, said the burden of proving customer liability in case of unauthorised electronic banking transactions will lie with the banks.The same time a customer will be liable for the loss occurring due to fraudulent transactions in cases involving negligence by a customer, such as where he has shared the payment credentials, the customer will bear the entire loss until he reports the unauthorised transaction to the bank. Any loss occurring after the reporting of the unauthorised transaction shall be borne by the bank.
In your case FIR was lodged and investigation from the side of the bank also completed. It is the duty of bank to protect your money .
You can approach the banking ombudsman and Consumer redressal sell for getting a remedy .Before approaching the forums you must understand the version narrated by the bank about the unauthorized transaction .Use the mail / details of account from bank as evidence.