Builder not paying back booking amount since last 2 years

I wish to advise you that I have been going through a financial matter and thought you may be able to please assist me in guiding on it. I had paid Rs.33,000,00/- (Thirty three lacs) to a reputed builder having their H.O. at Naupada,Thane (W) towards booking of a flat in their project at Naupada,Thane (W) itself called SINDHUSMRUTI in the month of April 2019. Total cost of the flat is 2, 30, 000, 00/- (Two crores & thirty lacs). It was decided to pay 33, 00,000/- towards the booking which I had paid as stated above and rest of the amount will be paid out of selling out my flat in Goa latest by July 31,2019 failing which deal would be cancelled. A MOU thereof between me and the builder was signed accordingly. Unfortunately I could not sell my flat in Goa within said period. I informed the builder accordingly vide my email that I could not sell my flat in Goa within the stipulated period and requested them to return back my booking amount i.e. 33,00,000/- asap as I was in urgent need of money for my daughter's master course in Australia. Out of the said amount, the builder has returned back only 25,50,000/- and I have been struggling hard to get back my balance amount of Rs7,50,000/- since the last two years. Regret, despite sending repeated mails, WhatsApp msgs and several telephonic calls, the builder is neither responding to my calls nor returning my amount. I was staying in Thane till Feb 28th, 2021 and had to shift to my native place Goa because of my severe financial condition. My humble request to you to please guide me on further course of action on the said matter.