UniverCell — cheated after taking advance

i went to univercell mobile showroom mantri mall in banglore to purchase samsung grand 2 on 02nd may. the sales guys told me that they have no stock on that time, so they told me to wait an hour for taking from their head branch then they got my mobile number, i waited a hour and we went to show room, that time the guy ask for full cash of the mobile and told to the mobile he will deliver in your door step but i didint agree, and after he ask an advance to pay after the bargaining he got 500 rs from me and he promised to me the mobile will deliver in 5.30 now the time is 10.30 i didnt got the phone still now what can we do?