Property dispute if grandmother thumb impression taken on blank paper

My mother is from kakinada ,we are staying in VSKP. my grandparents are having two children that is my mother and my uncle.My grandfather passed.My mother and her paternal family have ancestral property(Shops & site) from her grandmother, which should be divided to everyone, in which my mother was not given any of the property share. Before my grandmother death (my mother's mother) my uncle made her to keep hand finger impression on will saying during my mother marriage, dowry given to my dad and there wont be any share to my mother. We all came to know this once my grandmother passed away. we hired a lawyer he spent 4 years of time without filing a case by asking birth certificates, caste etc etc. after that we hired one more lawyer, case was filed but everytime its keepon postponing . i were planning to ask for a stay on shops rent as my uncle was enjoying shops rent from past 10 years without sharing to us. please guide me in this.