Fraud by DINING PLUS, False billing from my Credit Card

Location/place: DELHI

Name of company/service: DINING PLUS, MUMBAI

I received a call on 26.05.2012 from +911409802512 stating that he is calling from Dining Plus and he offered me discount card, which is free of cost. He also explained the benefits of the discount card. He asked my Credit Card no, which I refuse to give. Later he transfered the call to his supervisor, who told me that credit card no is only for verification purpose and he also told that he is not asking my CVV no which is meant for transaction purpose. On his several request I gave my HDFC Bank Card No.
On 28.05.2012 at 03.52PM I have received message from HDFC BANK TXN centre that my card has been debited by RS. 5499/- in Mumbai at Dining Plus. This is not an authenticated TRX as per RBI Mandate effective from 1st May, 2012. I immediately contacted HDFC Bank Customer Care and informed the wrong debit of RS.5499/- from my card without my approval. He told me that he is forwarding the complaint to their credit card department, he also advised that I should file my complaint through their Cardholder Dispute Form and drop in the HDFC Bank Credit Card Box, which I did on the same day.
You are requested to kindly look into the matter and arrange to refund my amount at the earliest.