Hello & Welcome,
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) 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 unit and START with KX-TG, but NOT have an "A" in it (that is for the cordless handsets & chargers).
2) How many TOTAL cordless handsets do you have with this system, and of more than one, are ALL handset having this issue?
3) What phone service provider (phone company) you have for this phone line?
4) If you have ANY other devices (phones, fax, alarm system, etc.) attached to this same phone line and if so, are they working properly?
5) Is the MUTE on the display FLASHING?