Non refunding of money by the builder

Dear sir,
I booked a flat from Hi-tech builders, Bhubaneswar in 2011 and they assured me it would be complete by 2013. SO far only half of the work has completed however I had already paid 70% of the total coat through bank loan. FOr the last 19 month the construction work has stopped as the builder was caught by the CBI with some land fraud case. Now none from the builder side giving any response regarding the resume of work. Even they are not interested to return my money back. So what to be done, please help me in this regard.