property issue

My great grand father brought a property which is divided among his two sons my grand father and his brother after that my grands father died in 1989 the land was divided between his three sons my father and his two brothers. son of my one uncle who is not leaving with his dad. my uncle told me to buy my land and I bought that land in December 2012 after seven month that is on august my uncle died. 7/12 is on my name & land is on my possession now in Feb 2014 his son filed a case on me ? What to do please suggest me what to do.