I had a phone that supported voice over LTE (volte) and wifi calling. Worked fine on another network, but that network did not have the coverage I need, so I h

I had a phone that supported voice over LTE (volte) and wifi calling. Worked fine on another network, but that network did not have the coverage I need, so I had to go with AT&T. With their '5g' 'upgrade', they stopped allowing voice calls, as those would go over 3g. Except, there was a period of time where volte worked fine on at&t - my guess is when they were reconfiguring for 5g, they accidently configured things to work the way they should, but then realized their 'mistake'. I had to get a new phone since I need the AT&T coverage.