Cannot receive calls with cellular on apple watch 6

My apple watch 6 gps/cellular only receives calls when I'm on wifi, close to my iphone. If i am on cellular only, and not near my phone, there is no indication/sound/buzz that I had an incoming call. I have a cellular plan attached to my phone (att confirmed and it worked until recently). I can see a missed call on my watch. I can call outbound with my watch on cellular. But when someone calls me it goes straight to voice mail. I was at the apple store for 2 hours troubleshooting and on the phone with att for 90 minutes. We have done the following multiple times:

updated the software on phone and watch

unpaired and repaired the watch

reset the watch as a new device

tried turning wifi and cellular on off in every combination.

no blocked numbers...multiple numbers have tried to call me

many other settings/resets.

ATT and Apple were perplexed. Anyone found an answer? I was one response that said turn off mirror my phone. It doesn't work either way..custom or mirror.

Thanks