Paghdi House in Demolished State for Redevelopment

The Paghdi room was in name of my Grandmother. There was also another room in the same building in name of my father. Landlord had created registered agreement with my Grandmother and my Father, to give ownership flats after redevelopment. Building went in redevelopment and was demolished, around 8 years back and due to legal issues/conflicts amongst partners, the work is yet not started. My grandmother expired 5 years back intestate. Amongst the legal hiers of my Grandmother, my father was staying with her and it also reflected in ration card. Landlord is giving alternate accomodation rent for the property in name of my father but not updating the records for the property that was in name of my grandmother to the name of my father and also not giving the alternate accomodation rent with respect to the property in name of granmother, to my father, since the demise of my grandmother. He is delaying giving some or the other reasons since such a long duration. Landlord is now insisting us to knock the doors of court. Landlord is denying to accept Release deed as document from other legal hiers, telling that, Release Deed is not allowed in Pagdi System. Would like to know, is there a rule that Release deed is not allowed in Pagdi System ? Also please suggest the least expensive legal paper work / procedure to get my matter sorted.