Flat cancellation

Dear Sir, In 2018 I have booked flat from Neptune Ramrajya and it was under subvention scheme and they have promoted and advertised that NO pre-emi till possession. But from Oct 2020 onwards bank sent letter for Premi to pay to bank whatever amount has done from bank at intiial level. Since 2 years construction also on hold and yet no progress. Builder has committed on e-mail that he will be paid reimbursement against Pre-emi but now he stopped to paying any pre-emi since Nov 2020. Bank also not keen interested to stop pre-emi as they don't have concern about construction is ON or OFF. And showing tripartite agreement that bilder or buyer will be liable to pay pre-emi if subvention scheme stop. There is no clue either construction will start or not in future and pre-emi to be paid any cost as bank stated. Already resignation and other required process has done and builder said will not return any resignation and GST amount if buyers goes for cancellation. Rera also not showing interest as they said in portal his possession date showing 2023 June as 8 months extended due to covid influence. Please guide further can we wait and pay regular pre-emi till possession or should I cancel flat? Because there are no concrete to develop construction and not adhere their commitment