Flat Dispute

I shakeel khan has bought a flat in Tara apartment situated at Nallasopara (east). Builder whose name is Humayun Shaikh known as Raju Bhai Builder has sold the flat at the cost of 10 lacs. Out of which we had to pay 50000 rupees to book that flat n to get the house key in April 2013.But he didn’t gave.Then He told us to pay more 1.5 lacs to get the possesion.we paid that too. But after getting the money he is not responding to us. Although we paid the money, he threaten us every time we meet or call him. He is not in a mood to give us the flat or our money back till date.Its more than a year he is giving us the flat possesion.we are very much worried.kindly help.