Refund of Money

Hi i have Booked 1 Flat at sep-2013,in Gurgaon shona road so i paid 10% as a Booking Amount through a property broker to builder , but Builder Got Approval in June-2014, So i Refuse to take this flat, and ask our money back, then Builder and broker said to me pay 10% more and take the allotment of the flat, only then you will be able to take back your money back , cause u will get a unit no, then only we will able to sell it to other customer, So i sign on (application)allotment letter, and paid 10% more Amount, now he is asking 10% more amount and send me a Builder Buyer Agreement, i refuse to sign the Builder buyer agreement,and ask to return my money, but now he is saying if u cancel your flat then 20% will be deducted of the from the earnest money as per application letter clause which is sign by me. so please let me know application form is bound to comply me because i haven't sign Builder buyer agreement , and if prelaunch is not allowed then how a builder can take the advance amount for the same , so please guide me what to do.