Redevelopment of building

Dear Sir, I have a shop of 300 square feet on ground floor of a building. I Had bought this shop in 1999 . The entire building was owned by one person(Mr. X) . Rest of the shops are on pagdi system. We had had paid 1/3 amount extra & got the shop ownership. We have registered document as a proof of the same. About ten years ie around 2010 back the Mr.X sold the entire building & plot area to a builder who is about start redevelopng the entire structure. Just for additional information the builder is redeveloping a entire slum area right behind our commercial building & desperately needs to make way for his project by redeveloping our building. The builder has verbally promised the other pagdi shop owners that he will make owners after redevelopment of the structure. Builder is yet to approach me regarding the same so My query is that 1) am i entitled to extra benefits since i am owner of the property? 2) Shouldn't i be getting extra space ie atleast 33% ( 300 +150 sqft) after redevelopment.