Air Asia — Fraud Offer letter

Address:

Bangalore Karnataka

Today in the morning I have received a link via sms to download my offer letter for Air Asia Company.
In the letter all details about interview is wriittem which seems to be original however they have asked for security deposit of 10k which I think it shouldn't as they requesting the payment today itself.
I had call on the number provided with name as vasant kumar (HR). I had a word with him and he assures that it is genuine offer letter but on research I havent found any details about him on air Asia website or on Google or LinkedIn.
Please take this very seriously as I also have the recorded call and kindly revert me back with the resolution asap.