new apple watch 9 cellular not work error

OK, I bought my son an apple watch 9 wifi/cellular. When setting up the watch everything goes as planned except when settings up cellular. It keep getting an error code EDS4100 " It appears that you have deleted your ESI or it is missing. Then if i click OK it pops up NumberSync error "SoftSim flow Completed DataActivationController.doneSelected();

I have spend almost 8 hours combine on the phone and in the store. With no success. I was told someone will contact me in 24hrs.

He originally had an apple watch 4 that was working but I wanted to upgrade. This is a standalone watch/number that should work by itself. He doesn't have a phone. So i set the watch up using my phone and selected set up for a family member. 

Has anyone experienced this problem? If so what was the fix. Thanks