How to get the house from builder?

3 yrs ago we bought a duplex from a builder. He said to hand it over in 18 month but he even didn't started the project. After 18 month of shouting he finally began the project but after little start few people holding weapons came and stopped the working. Builder lied to us that he has some money to give them and nothing more. But later it became more frequent. We then came to know that the property he has sold us was bought from another builder by him but he didn't pay him fully. And what more is that the 1st person had mortgaged it in bank and sold it to our builder and then builder sold it to us. However we didn't get any mortgage sign in EC. We have the patta of the land. We went to the police and builder signed he shall clear the bank loan by buying it in auction and bank said him to pay 90lacs for whole land ( 15 buyers) he paid 19 lacs and didn't pay even after the said date expired. He hasn't even provided electricity in project nor road. And in front of our house road is narrowed compared to promised specs of building. Please help . He threatens go to whoever you want you won't get refund it's my money. He has 3 showroom now and govt tenders too.