Needs clarification ?

Sir, I had made an agreement to purchase a flat from a builder in 14.02.2018 Payments were also made as per the agreement in all respect except the registration fee since the builder is not in a position to register(sale deed registration) the property to any of the purchaser because of their own legal issue ? But completed the project within completion period (01.02.2019), got the OC on 3.10.2019. The builder handed over the property keys for interior works and many are staying in the property but PC is being issued by the builder from the Month of November 2019. The delay happening in the registration of sale deed is due to builder own legal problem? Because of this there is an uncertainty situation in registering the property? The builder suppose to maintain the property for one year then association to be formed legally as per agreement but they formed Adhoc association (LEGALLY not done as per the Apartment Ownership act of the State), trying implement the maintenance and defect liability period with effect from Nov, 2019 and demanding maintenance charges for the expenses over and above the corpus interest amount? And violating their own agreement to sell, conditions? Builder is trying to impose such charges and informing the same through Adhoc association? Not formally to the individuals? Am I liable to pay maintenance charges in this Situation? Or we are entitled to claim an interest on our purchase value? If so what will be the rate of interest? Since the association is not registered as per Apartment Ownership act of the State? Please give a reply. Thanks Manju.