Straight to voicemail, no ring, spinning circle under call forward setting.

I have an iPhone XR that operates normally except that it won't receive phone calls. I can make calls with no problems, but when someone calls me the caller hears a ring several times and then goes to voicemail. I don't get a ring, missed-call notification or a missed call on my call history. I just get a voicemail notification a few minutes later. I've tried looking at my settings and everything seems in order (they were imported from my previous iPhone) with one exception: When I click on the "call forwarding" setting I just get a spinning circle so I can't see what that setting is or change it. I've reset the phone several times and that hasn't helped anything. Any suggestions?

BTW, spent over 10 hours with Boost mobile and 2 hours with Apple this morning trying to fix this. So frustrating. Been unable to fully use my phone as a "phone" for 6 weeks now.