Registry & stamp duty paid - need to cancel

Hi There, I had recently bought a resale flat in Pune, Bavdhan. Gave 2 Lakhs as token amount & paid 2.19 Lakhs as Registry & Stamp Duty fees. But after verification I got to know that Sanction Plan which builder has submitted is not valid. It has only 3 floors mentioned in the plan with no shops and area mentioned is also too small than the agreement figure (original between 1st owner & builder). but in actual, there are shops at the front & 4th floor is also occupied by tenants. That property is also not registered under Grampanchayat. All these facts were hid by seller to me and now after getting all those facts known, i want to cancel the Agreement to Sale. My queries are, 1) How much of the paid amount will I get as refund if I can the Agreement? 2) I want to file a case against seller under information rights so that nobody should get his/her hands burnt due to these kind of mistakes. Please advise as its very urgent to understand & take appropriate action. Thank you in advance, Chaitanya