Hello & Welcome to Just Answer,
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) WHEN did this issue first began - or was noticed?2) How many TOTAL cordless handsets do you have with this system, and if more than one, do ALL handsets have this same issue (garbled messages)?3) What phone service provider (phone company) you have for this phone line?4) Do you have ANY other devices (phones, fax, alarm system, etc.) attached to this same phone line and if so, are they working properly?
5) Do you notice ANY other noise on the line - when speaking with other callers?