property/cheating

my maternal grandmother (mgm) has one female child (i.e. my mother) with her first husband. after sometime (years/months i don't know) mgm lived together with her 2nd husband had another one female child (i.e. aunty) (mgm getting his pension after he died some years back). We have constructed in 1997 a building in my mgm's old house place (i.e. mgm's 2nd husband was bought two portion old house on mgm's name in 1977) with two portions, in one house my family (my mother, father, brother's family (wife, female child), is living and in 2nd house aunty family is living. after some years 2nd stair constructed, and after some years 3rd stair constructed. Now, i am living in 2nd stair from 8 years and my brother is living in 3rd floor from 8 years. Now only i got to know that mgm has two husbands and about this property. as my parents are very innocent, the aunt's family used my family to construct the building right from beginning as they do not have sufficient money most of the money spend my father. Now mgm and aunt family is seeking to get out from the house our families (1st floor (my mom and dad), 2nd floor (me, my wife, my boy), and 3rd floor (my brother, his wife and female child). my brother is going to move to rent house in few days. all property and water tax papers are on mgm and aunt's name, my current meter is on aunt's name remaining all 4 mgm's name except 1 is on old house owner's name (total 6 current meters). before constructed the house we lived 2/3 years in old house. MGM's pension give to her daughter only (aunt, as we thought aunt has two female children that is why we didn't ask pension money anytime, now aunt's one child is govt. teacher and 2nd child s/w engineer now in America). What type of action we can take on them. What right my mom has on this property. Can we file cheating case?