Beware of phone calls from people working with Airtel

I received a phone call from a lady named Anjali(9004947628)working with airtel in borivali, who introduced me to a new scheme of aitel. The scheme was that i'l be getting 5oomin talk time free with monthly rent of just Rs49. She told me that i will have to pay Rs600 for the sim activation, of which Rs500 i'l get back,i.e. the amount will get deducted from my bill. She noted down my address and the next day one boy named Jay Jatankar came to my house. I checked his i-card as well to prove that he was from airtel.He collected the money and gave me one receipt. The scheme has not yet got activated and the lady who called me up no more answers my call. When i went to airtel office in borivali i was told to lodge a complaint on a sit nodeel.officer.in
If you visit this site you will hardly see any relevant location to complain.
how do i approach this lady now? How will i get back my money?