Citibank — Fraud ATM withdrawal

Address:

New Delhi, Delhi, 110058

Amount of Rs 20000 was withdrawal from ATM without my ATM card .As i have not lost neither shared any my card or account details .My ATM card is with me and just received the message of Cash withdrawal on 4th March 2016 10:46 am.
I called up the bank informing about the same .They have asked me to log a police complain and will check it .No assurance is provided by bank for the cash refund .Its not that i lost my card and someone has used it .
Bank should keep the track of all such fraud transaction
Kindly help