Builder is not repaying the advance money what to do.

hello sir, I have paid 1lakh rupees as a advance for a group house.the total cost was 16,5lakhs but the builder is not building the property as we wanted.the building plan is not so good(sewage pipes in kitchen) and he is asking more money (for small cubboards,cement plates in kitchen,the wood used for doors are not so good).so we said we cant proceed as the building plan is not so good.Apart from this the house which we are buying is mortgaged and he didnt tell us and managed some how from his end with the bank representative to get the housing loan sanctioned for us. after seeing all these things i said i cant proceed and asked to repay my advance amount. Now he is saying he will pay back the advance only when somebody else purchases the flat/grouphouse.Please let me know what can be done to get my advance back. regards raghav