Phone was working fine but cell service stopped.

iPhone SE 2020.  Phone was working fine, but I noticed on the Xfinity Mobile "Devices" page, it had a button that said "Activate Device" or "Ready to Activate".  It seemed weird since I didn't get a new device, but I tapped on it.  It went through the activation process, but then the cell service stopped working.  No bars.  Still works on WiFi.  Tried turning it off an on.  Tried removing the SIM card.  Tried doing an eSIM.  Nothing has worked.  I know it's an old phone, but that's not the problem.  There are four iphone SEs on this plan.  One is exactly the same age.  I was looking at new phones through the app a few weeks ago, and I think that's when the button to activate showed up.  Phone has been working with no problems until I erroneously tapped the button.  How do I get it to reactivate cell service?  Thanks you!!