Can adivasi reclaim their land if it is sold by their ancestor under judge supervision

I and my family are residing in a house. The house is in Adhivasi Land. That land was purchased by my grandfather around 50-60 years ago and the Registration was also made under Court's Judge supervision i don't know his name.Now after so many yesteryears there family wants to repossess it. Neither of the person who signed on the registration deed are alive. Even their family are threatning us. Please advice as soon as possible.