The best thing for you do in the current situation is to try and find out the name of the company in Doha you will be working for and then check with the company if such a job exists and whether they have this agent in India. That could make you a bit sure. Check with the agent in how many installments the total amount will be deducted.
It is difficult to say at this stage if the offer could be a fraud or a genuine one. There are simply so many "games" being played and new ones by such agents to cheat people out of their money.