Brother asking share in land, legally registered in my name by mother

My grandma had 5 sons and 3 daughters. My father is last child. my father is took responsiblity of his mother. My grandma had a land So my grandma is legally registrar to my father in 1992.my father is built a house in 1994.Know a days my father brothers are issue to this land. We have also same share on the property. You don't response.other we are send a civil notice to your home. What we do sir.