Hello & Welcome to Just Answer,
Sorry to hear of the issue you are having with your phones.
To help you with this issue, may I ask:1) The Model Number of the MAIN BASE UNIT of the phone system you are working with? That should be printed on the bottom or back of the main base and START with KX-TG (and no "A" - which is for the handsets only).
2) What phone service provider (phone company) you have for this phone line?
3) Does the time change to the "whatever" time zone - almost immediately after you receive an outside call?
I see it has been a few days and I just wanted to follow up to see if you have any more questions concerning this issue or if the issue was resolved.
I look forward to any further questions or results that you may have.
Thanks, ***** *****--. .-(im)