I have frontier.com landline phone service, how do I block a neighbor?

I know there is a feature on the phone that says I am not accepting calls at this time. What numbers do I push to activate it? I am packing a couple boxes to send my Grandson in Iraq, he's in an outpost digging wells, where it's meals ready to eat,no hot meals, what my husband used to call K rations, and she thinks the army sets tubs of goodies around to eat, and this may be true on the bases, but he does not even have showers where he is. She keeps saying "Oh the poor baby", saying he is pulling my leg, and it's starting to get to me. Thank You, 75 year old Grandma