Redevelopment Agreement Signed 24 Yrs Back

Dear Sir/Madam, There is a prime plot in mumbai, which was a SRA chawl system, 24 years back a builder approached us and decided to give us 225 sq ft carpet area in total there are 1500 people. The agreement was signed after that we did not hear anything from the builder nor the committee member. In the meantime the builder in the last 5 years started building the houses, demolished some house and for the demolished houses gave the transit accommodation. After 5 years he constructed a building in the meantime the rule for 225 sq was scrapped. For the people whom he made the transit accomodation refused to enter the new building demanding new area. Now the builder wants our society to take possession of the new building. From the last 24 years there was no written communication with the builder and we society members. The early agreement which was signed by us the society committee is refusing to give, also the agreement copy is not there as it was taken by the committee member and did not give back till date. In such a situation after the agreement was made, what is the life of the agreement, can it run into infinity. We need a lawyer who can guide us for the same.