Hello & Welcome to Just Answer,
I'm Greg and will do my best to assist you today.
Sorry to hear of any issue you are having with your phones.
To help you with this issue, may I ask:
1) The FULL Model Number of the phone system you are working with? If this is a cordless system, that model should be printed on a sticker on the bottom or back of the MAIN base and START with KX-TG, but have NO "A" in it (that is for the cordless handsets ONLY.
2) Do you get this "private caller" for ALL CALLS coming in?