Apparently the world is done with 3G. And that means older phones may have stopped working.
I have service through Lively/Great Call. They are sending new phones to those with issues - supposedly just the old flip phones. But you have to get through to them to ask. If you know someone that needs help they should go to Lively's Facebook page and send a Message - then sit and wait for a response (it can take up to an hour). They are apparently overwhelmed with emails and not sending responses right away, so that Facebook page is your best bet.
If someone has a Jitterbug Smart phone that isn't working you just need to tell it to upgrade:
options
view phone settings
android settings
... more
cellular networks
enhanced 4g LTE mode
I know nothing about other brands of phones, but for Lively/Greatcall it took me two weeks to finally get this resolved. I decided to post in case someone else might need the info.