Whom do former Jehovah's Witnesses believe are true Christians?

I am not a Jehovah's Witness. Most everyone stays in the religion once they are in it. A few have left and are said to have gone back out into the world. Many families have been disowned when one of them becomes a Jehovah's Witness. They are not supposed to have contact with family or friends if they are not Jehovah's Witnesses.