Hello Norma & Welcome,
I'm Greg and will be assisting 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 unit.
2) WHERE are you SEEING (or hearing) the "memory full" message?
3) What phone service provider (phone company) you have for this phone line?
4) If you have ANY other devices (phones, fax, etc.) attached to this same phone line and if so, are they working properly?