Division of Land b/w 3 sibblings

My father and my 2- elder uncles bought 2 properties together as we have common business. My father is 3rd number brother , other two are elder than him. After some dispute my father separate from common business and open its own business. But other two uncles remain join as there wife's are also sisters, so they are like 1 family. After elder uncle death , his 3 sons and uncle-1 doesn't want to give any any property to my father. But after some fight and by calling relatives we have divided our property and signed on plane papers. Property is divided as one house is divided half in b/w elder uncle-1 and my father . Second house will be given to uncle-2. which makes that each one can build a good house. But now they do not accept that partition signed by them and saying that we will only get 3rd part from each land . so that we are not able to build our own house. house in which my father and uncle-1 family is living is build as 1 part is fully build , 2nd part is half build and third part is empty. Both uncle family is claiming that build and semi build part are those and they want to joint there portion and gives us 3rd part to us which is empty. but actual they uncle -1 uncle -2 divided property in such a way that each having 1 house of 2/3 area. we have 2 properties of 1/3 rd area which is of no use as area is too small to build a house. So can u please help how to claim the property . If property is divided only 1/3 then how will law decided that which part comes under which person. Please helppppppppp. Thanks Mukesh Sharma