[Resolved]  State Bank of India — Forcefully imposed service charge of Rs 6180 against Privilage Circle Offer of SBI Credit Card without my consent

Dear sir,
As per the discussion with one of Customer Care Executive of SBI credit card, they informed me that i have been selected as one of the financially secured customer from Kolkata. As an award i will get few benifits from SBI Credit card.For that reson they wanted to know my card no. and my address.At last they informed me that i have to pay Rs 6180 to get the award.At that time i was so confused and suprised i did not say anything.I informed them i have to check the thing from internet after that i will think for the award.The representative discouraged me to do so.
When i checked the SBI card's website, then it has been cleared to me that i was cheated.At that time i have immediately sent a meil to SBI card for cancellation.At the very next day i personally contacted the representative for cancellation.They told me that they could not cancel the bill.After that i have sent 4 emails for cancellation and lodged 2 complaints at SBI card's website.
Finally they raised a bill against my card and claimed the money.
Please suggest what to be done.