Buyback Scheme not delivered

Place Bangalore . signed a Buyback agreement with Seller in 2017 for 2 years paying 10% of the property amount and the loan was opened in my name. with a commitment of 100% returns after 2 years and Loan transfer to builder , buyer or cancellation . The builder gave all excuses of not having money to return my interest or close the agreement in 2 years, instead requested for rollover or extension for 2 years until 2021, and pay 8% interest for delay of principle and interest. all this while the builder was paying pre emi , also asked help to approve moratorium to bank for COVID times for 6 months last year ,now suddenly has sent email to all buyback customers including me that they are unable to pay Pre -EMIs as they want to focus on construction first. What should I be doing at this stage, project is looking like will take 2 years at least to complete with the way the progress is going on. I am not willing to pay Pre- emis and I want my money invested back with interest and want out of the Loan. Agreement clearly mentions builder is responsible for loan.