The Phone is Ringing!

We have three cordless phones and a base with a speaker phone only. However we can seldom find a phone. Sometimes we can't hear it ring because it was left somewhere in another part of the house and the only way we know it is ringing is because it is announced on the TV set. When we do find a phone and answer it, it almost immediately sounds low battery or just goes dead from the strain of being answered. At one point we put numbers on the phones to find which one goes dead the most frequently. We found that phone was number three. We have also found that number one is missing, presumably dead by now. When we do hear the phone ringing and go frantically searching for it, we usually find it is from "Out of Area" or "Hilton Grand Va" which we had no interest in answering anyway.