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) Has the PHONE CORD (at the MAIN BASE UNIT) been MOVED or PULLED at all? I only ask because these symptoms usually indicate a POOR CONNECTION to the phone line.
2) What other phones do you have connected to this phone line?