Refund of advance paid to builder

Dear Sir, My name is Swapnil Fase and leaving in Ahmedabad. I purchased one property at India colony, Hathijan in Ahmedabad. I paid booking amount around October, 2010 with booking amount of 50,000. At the time of booking I have been informed by the builder that have to complete 25% of payment within 3 months and then he will hand over property paper after 3 months. At the time of booking I was given assurance that I will be given possession by end of December, 2012 or June, 2013. I completed 25% of booking amount as per schedule given by builder. However, builder didn’t gave me property papers to arrange loan in time. It took 2 years to him to give me loan papers. This created doubt in my mind that builder will not give possession as promised. Hence, I cancelled my booking and asked for refund. At the time of cancellation, builder’s representative assure me that refund will be given in one month. However, till date I have not received my refund. After cancellation, I started getting answer from builder that refund can only be given once property is sold to other person. We have received information from market, that financial condition of builder is not good and he will not refund the money. Now, I have offered him to purchase the same property on old rates so that I can have my money back. To this builder is claiming that they can not offer me flat at old price. In view of above, please guide me how can I get my refund from builder? Warm regards, Swapnil Fase Mob. No.: +[deleted]