Revell Orchid Dhanori not returning complete refund for flat booking.

Q: I have booked a 2 bhk flat in Revell Orchid Dhanori in April 2012.At the time of booking they informed me from 1st may stamp duty and govt. tax prices will increase, but if we book before 1st May increase will not valid for us. In the application form it was writen that I will be ok with the prices hike in govt taxes", but they informed this is a common application form format and the prices hike will not be valid for us. I paid 2 lakh booking and they informed within a month I have to pay more 6lakh,and then bank will pay as per loan. Now after month when I went for registration in May 2012, they are including prices hike and want me to pay 4 lakh extra.Now after a long mess and as they are not upto there words,I am cancelling the flat and want my complete booking amount back.They are not returning my complete amount and I need some legal or any help...If any one can please help to get right direction...it will be appreciated.