Not paying booking amount bu builer

Dear Sir, i booked a flat in banglore 2013 and they commit me to give possesion in dec 2014 but they fail and yes there is no written commitment from builder. in june 2015 i cancelled that flat and purchase another one. now i am followup with builder from last one year to return my money which is Rs. 652000.(20 % of flat cost). in last meeting they offered me another property because in that propert they have only G+4 approval and they are making 15th floor (as per my knowledge) any way i am not interested to take there property because i already purchase another one. now they are denaying to return my money as they dont have fund. i have agreement(Memorandum of understand ) but in this there is no clues for cancellation but in booking form there is mentioned 30 days they will refund booking amount. now what i have 1. (Memorandum of understand ) 200 bond paper 2.Payment receipt from builder 3. payment detail through my bank. please help me to the process how can i get my hard earn money back.