Issues with Private Builder

Hi, We have bought a house from a private builder (builders who build few floors and sold them off) in 2011. The builder built 3 floors in approx 2000 sq ft. and a ground floor as a parking. He kept the entire 1st floor with 4 BHK and a huge drawing room, storage etc for himself, while 2nd and 3rd floors were divided into two 2 BHK flats of 1000 sqft at each floor. So each floor is having 2 units with 1 car parking allocated to each flat. In total the building is having 5 owners. There is no documentation of the terrace above the 3rd floor in any of the registries of 4 flats. We are facing the following issues now: - Who will have the right to terrace since there is no documentation so far on this? - How much building maintenance should be borne by the builder as he himself stays in the double of the area, having double parking. They have also built a small room in the parking area and running a play school there, however they are not willing to pay the maintenance. As of now the total maintenance is divided into 6 parts (1 of each flat on 2nd and 3rd floor and he himself pays 2 portions). - Also they keep on doing constructions in parking area for their personal benefit. Is this valid? - The flat of 3rd floor is suffering from seepage issues due to drainage issues at terrace. Despite many reminders, he has not taken any action. What could be the possible legal action taken in this case? Do you think filing an FIR would help? Thank you in advance for your kind opinion. Regards Poonam Saini