Builder is not returning the money

Hello My father booked a plot in closed residential area in madhya pradesh. 1. Builder have taken more than 30% of amount with in two months of booking 2. Initially he kept saying we will do registry in next 15 days or months and it happened until 8 months 3. Then he started making excuse that 1 bank is not approving and push us to go to other bank. 4. Once loan is approved then he denied to do agreement and said you need to pay 15% interest for of one year. 5. We argued with him he said either pay me additional or take your money with interest 6. We were kind of forced to take our money back, he said he ll return in 10 days .. next day he said he ll return 3 months. 7. Its been more than 4 months, he have not returned money to my parents every other day some other execuse he is making up. My parents are living on rented house, builder have mentally tortured them for past one year ... either demanding money and now when they have lost hope and not even getting their sum back.