Termination Of Redevelopment Agreement - Buyer's Stand

Hi, I have bought a flat in an under construction redevelopment project in Dahisar, Mumbai in 2012. The builder has given allotment letter which has flat details and payment schedule. Now since 2.5 years the construction is very slow and builder has only managed complete the basement parking and plinth. Builder promised me the possession by 2014 which is already gone. This timeline is not mentioned in the allotment letter. Since almost last six months the work is stalled and builder is not even giving rent to old tenants. The old tenants have terminated the development agreement and POU. They are thinking of appointing a new builder now. Questions, Can the old builder be terminated solely by society? If the builder is terminated, what stand does buyer has? Will they be accommodated with new developer? Or do they have to fight with old builder in court? Please suggest some way outs? We are 32 buyers in total and are suffering a lot. Thanking you in advance. Milind Sawant