VAT refund from builder

I have booked a flat in bangalore during pre launch and after 6 months they sent me agreement which I did not sign due to their strict clauses and decided to get a refund. They refunded the base rate and they are not refunding the service tax and VAT. Finally they agreed that they will refund service tax after they resale the flat to someother person. But they are saying that VAT cant be refunded. Now my question is 1. No sale happened between us, so why did they pay VAT? 2. The builder is saying they cant do anything because they have paid the VAT to the government. So as an individual how can I claim a refund of VAT and what documents do I need?. Thanks Prateek