dispute over land

Disputes over land Sir my grandfather has 3 son and 2 doughter and total land is 33 acres.after his death at1983 my father has 11 acres land and other two auncle have 22 acres land.my father is simple and easy to make fool.at 1992 uncle and father decided to grant land to grandmother for her living good.my grandmother live with my uncle.my father and uncle give 9 acres land to my grandmother by register to her name and it is decided during registering process that after her death the 9 acres land distribution to all 5 sons and doughter.but at 1998 my uncle made vasiyat by fooling my grandmother due to her simple and uneducated. In vasiyat it is claimed that all 9 acres land will give to my uncles son.after my grandmother death at 2010 they nominated all land to their sons after one week of her death. Then we register a court case to my both uncles and it is 4 years to beginning of case. I want laws in that case and how you recommend me over this case. I will be thank full to you for this Regards Rahul