I want to cancel my flat purchase but unfortunately Sales deed, Construction documents registered

I want to cancel my flat purchase but unfortunately Sales deed, Construction documents registered, MODT got registered in Chennai, Tamil Nadu. Reason for cancellation is even after registration builder is trying to cheat me and has done lots of fraud with me. Right from the booking of flat. I have explained everything in detail below: At the time of booking assistant sales manager of builder promised 605sq.ft. (total build up area) and 424sq.ft. (Carpet area) with lucrative deal of ZERO Down payment with free 3 years maintenance, free 15 years club membership and covered car parking, all in Total amount of Rs.2820000/- (Twenty-Eight Lakh Twenty Thousand only). Sales assistant manager also insisted us to pay the money immediately as deal is about to expire. And demanded Rs.100000/- (One Lakh) in cheque and Rs.20000/- (Twenty thousand) in cash. Sales manager also informed us that total cost of house will be more than 35lakh, and I only need to pay Rs.2820000/- and rest will be paid by Amarprakash Developers on my behalf. He also explained us that under ZERO down-payment scheme builder will deposit 10% of the total cost of the flat to my bank account and withdraw the same via my bank cheque. So Amarprakash Sales manager also demanded blank cheque from me. In total Amarprakash Sales Assistant Manager demanded Rs.20000 in cash, 1Lakh cheque in favour of Amarprakash Developers and one blank cheque so that Amarprakash developers can deposit 10% of total flat cost and withdraw the same from my bank account. On this I sensed money laundering, so I asked question to sales manager but he took me on confident by saying that it’s not a money laundering. Amarprakash person will gift me gold coin which I have to return them back and that gold coin value will be equivalent to 10% of total house cost. As we didn’t want to miss such a great offer, we immediately gave whatever sales manager demanded. Because sales Manager of Amarprakash assured me possession within 20 days of booking as the flat is in ready to move in condition and GST free. But later on after 2 months builder said that they are not giving covered car park, and club house in that amount. So, I agreed to pay 300000 extra for car park. Now the cost sheet which builder provided to us has 2820000, on Sales deed cost of house is 3300000, and builder has another cost sheet on which cost of house mentioned is 3516320. So, finally i decided to cancel the property as builder still trying to get extra money from me. As builder has not credited 10% of the total cost of house to me which builder was supposed to pay under their GOLD SCHEME.