Regarding Grandfather's Property

Hi, I'm Rahul,my age is 22. My question is all regarding to my Grandfather's Property.He had 3 siblings he's 3rd among 4.Their father had 7acres of land. My Grandfather have 7children Women:5,Men:2. As we were moved out from the village for personal reasons.Two of my Grandfather's siblings are occupied the full land.When we tried to resolve the situation by measuring the land equally,they have provided some fake documents to cover all the area.As this thing is taken serious from the point where my Grandfather died(a year ago). Two sons of my Grandfather are abroad. Only his daughters(my mother,4 aunts)are here.(granpas siblings) They are Forcing us to take less than 0.2acres share in the name of my Grandfather. So we don't know what to do! Shall we cancel the URD and reclaim the new one? Or what are all the process left to move further to bring an equal share((7/4)=1.75acres).What are all the documents required to solve this problem legally. I kindly request you to guide me with this. Please... Thank you,