Hello & Welcome to Just Answer,
I'm Greg and will do my best to assist you today.
Sorry I didn't see your question earlier and to hear of any issue you are having with your phones.
To help you with this issue, may I ask:
1) Are you SEEING or HEARING this "full" message?
2) What is the EXACT "full" message you are seeing or hearing?
3) What phone service provider (phone company) you have for this phone line?