Is Flat Booking Agreement Legal on 500/- Rs stamp Paper Noterised

A builder launch a scheme says that 20% during the booking and rest is EMI to Builder Directly.. He called it 0% loan. We saw the Documents some of them not completed in the year 2012 and did agreement which is on 500/- Stamp paper which he called Booking Agreement. Following points he mentioned in Agreement. 1: He is responsible to make sure all papers are ready. 2: Stamp duty registration will be done after 80% amount completed. 3: 35% deduction for cancellation. 4: No Date committed in agreement for Flat possession. 5: He has authority for cancellation if payment not done. 6: and other some of points which are there. I have paid around 40% amount of property and found that Constructions has stopped from 1.5 year and no progress. He did not given possession to anyone, where 400+ people booked property there. When I asked for possession date he said did not answered and so many times verbal false commitments. After enquiry we found he was taking bookings even he has no NA(Non-Agriculture) papers,EC clearance, PMRDA certificate and Construction was stopped due to some cause, when we complaint to him he said the agreement we did it is understanding agreement. No When I asked my money back there will be 35% Deduction, What I should do, Going with this deal no commitments from his about possession and cancellation this deal I do not want to deduct 35% where property cost is now increased by 20% and he can sell property to anybody with higher amount. Can I ask for full refund, where as I have all bank statements paid by cheque. Please suggest..