Consumer Redressal

I have booked a flat in \'Sirocco Grande, Punawale\' at Pune in March 2014. I have paid 8 lacs to the builder. As there is some problem and miscommunication, I have cancelled my booking on 21st Aug 2014. Agreement is not done till cancellation. Now builder saying 1. he will refund amount only when he sell flat in open market. where my opinion is he should refund it immediately. 2. He is saying he would cut 15 % amount as administrative charges i.e. Rs.1,20,000. I am not agree to this, as there is no such agreement happened between us at the time of booking. 3. Also I have paid service tax of Rs.8,180 which he is saying, he already paid to government so he cannot refund. My point is service tax can be adjusted in his future payments. so he can refund it to me. 4. Also I have given 8 lacs to him in the month of march 2014, 6 months ago, so I should also get the interest of that amount which he is not agree upon.