What to do if father's brother is showing bad intentions with property

Hi, We are from Mumbai and my uncle with his family stays in native where we have some property including a old house. A year before my dad n uncle along with their 2 trustworthy nephews decided to divide the property equally to avoid future conflicts. While doing so both of them i.e my dad and my uncle agreed to whatever came to their stake. All this was done informally but written on normal paper and both of them including the nephews(as witness) signed the paper. Now after approx one year my uncle is behaving rudly with my dad moreover he also indirect saying that I have been living here for long so all this belongs to me, moreover he also asked my dad to stop coming to native and let go everything for him. Also his daughter in law said that my sister don't have any right of talking as she will get married someday and does not belong here. Can someone suggest me if and what action can we take against them ?