Committee decision on illegal construction

Sir, I have purchased flat in junuary 2012 while construction is in progress. I have taken possession in february 2014. my flat is in the society corner and on the first floor and just near to the builder office (which was not a part of whole appartment scheme plan) which is temporary in nature. Also as per brochure and plan of apartments scheme it is not under my flat. after possession i have rented out my flat for about 16 months and society was under the maintainance of builder. In July 2015 builder approched to society members to take over and form the housing society so that they can handle the society maintainance. also yet builder to sale 10-12 flats available for that he acquired his office. my flat was vacated (i was not live there) since August 2015. Meanwhile society was formed and registered under co-operative housing services private limited and taking over charge from builder.​ in this process society arranged several meeting with member of flat and i was not informed through phone even. and they have decided to take over charge(without my concern) of builder office(which was not in plan) for society storage and office when builder will sale out all flats. now i came here to live from january 2016 and came to know these things. i talked to builder about this that the office is not in plan and i am not willing that the office should be under my flat due to lots of security reasons(any body can climb on my flat from this illegle construction) even other neutions also over there due to that. Builder told me untill and unless socity will ask to remove i will not remove it. Menwhile in January and in February i have given in written to the president/secretary to remove/ask to remove this but they are telling me this is society issue and to take decision in meeting yet they have not taken any decisions. Sir please suggest what should i do about this things.