Redevelopment flats saga never ends, there are no laws to protect ourselves.87

Dear Sir/Madam, We are based in Malad/Kandivali west and our 1972 building is undergoing redevelopment. The carpet area as per architect measurements is 440 Sq Ft per flat but the builder is insisting that the Assessment & Approved area as per BMC records is only 392 Sq Ft but they have not shared this paper and old sanctioned plan with us. He has offer of 27% on this BMC approved area where in the final flat will again come to only 504 Sq Ft. We currently have two adjoining or Jodi flats which allow us to make a massive living room 6.84 x 4.78. And we have currently 3 bedrooms with independent access to each bedroom room which is 2.78 x 3.39. The kitchen is decent size 2.69 x 2.23 then we have general toilets and atleast one master bedroom toilet. Overall the planning in existing bldg is very good. Now in the new bldg post redevelopment We will get 1.5 BHK in return of 1 BHK!! in floor 5 we will get 1 BHK and another flat exactly above on floor 6. We lost the jodi flat advantage. The plans for new society are like railway ka dabba we are getting bedroom and toilet access from kitchen like a chali or tenanted flats. Now the builder and society officer bearers claims that what you are getting is fair as per the law as each of the 1 BHK is 504 sqft. The society management is hell bent on going ahead with redevelopment and says that our building is unsafe and BMC will evict us if we do not go for redevelopment. Our Bldg has received C1 certificate from MGMC/BMC. Society has definitely failed to negotiate with the builder but there could be hand and glove understanding between builder and society members. Society says why the jodi flat issues were not raised before but the owners and occupiers are 82 and 83 years with children NRIs they dont know the law nor attended any society meetings hoping that their interest will be taken care. But now realize a big compromise in life quality post redevelopment and these new flats are not useable by us. Builder is asking 1 crore more for single area big flats which are only available higher floor where flats with area 986 /1008 sqft are available. Without adding much area just for floor rise builder is demanding 1 crore from us for 986 sqft flat where as 1080 sqft flat builders says is beyond our means. Else we must accept two flats on different floors. Everyone saying there is no laws to protect me as I dont have BMC registered jodi flat and infact the maharastra govt is going to impose penalty for not emptying the flat in time. Is there any way we can find out from BMC, the old sanctioned plans/ carpet area/Approved/Assessment area/ ? Is there any way to expose this immoral act, legally? Is there any way I can get a jodi flat/ single area of 1004 + without paying 1 crore . We don't have more than 10 lakhs to spare but builder has refused our offer to swap flats in 10 lakhs he wants 1 crore minimum but we cannot prove this in court as it is private conversation. what should we do.