Mobikwik — fraud transaction with debit card

I wish to bring to your notice, a fraud transaction which took place yesterday, using my father's debit card. He got a call from the number [protected]. We had a transaction refund pending in mobikwik and filed a email to customer care. The person claimed that he was calling from the mobikwik to resolve. He asked for the debit card numbers and the one time passwords. As my father does not have much knowledge about the internet banking process, he was easily duped, and gave off the debit card numbers. As soon as the call was over, he got an sms from the bank, stating that a transaction of rs 11000 from one account and more rupees from other bank accounts was made from his card. He was quick enough to get the card blocked and also filed an fir with the local police. I have sent a mail to the backend department of mobikwik.com which handles all fraud complaints ([protected]@mobikwik.com), but haven't received a reply yet. Hopefully the transaction could be aborted at an earlier stage. However, i haven't received any response yet from any of the sources. Could anyone suggest a better approach which will help me in getting back my money