Has AT&T cut service to Consumer Cellular in western Kansas?

It might be useful to find out the specific model of phone you have?  And how recently has the coverage changed?

It has been many months since ATT cancelled 3G coverage.

The ATT Coverage map shows a lot of 5G and 4G LTE coverage for that area.  

The original phone was a Doro 7050 which is a 4G capable phone. The new phone is a Verve Snap which is also a 4G capable phone.  And the service dissappeared about the same time as AT&T stopped 3G.  I see the AT&T map coverage but that doesn't mean that the AT&T subsiderary companies like Consumer Cellular are still receiving service. But thanks for the suggestions & Happy New Year to you. :)

This tells me that either the phone doesn't support VoLTE on ATT's network, or it is configured wrong.

Not surprisingly, it isn't listed on ATT's whitelist of supported phones, but that list doesn't necessarily list all phones that may be approved by MVNOs.

In settings, is there an option for LTE Voice and Data?

Also, maybe consumer cellular doesn't have your account configured for VoLTE.  Losing coverage when 3G went away would seem to indicate that the phone or service wasn't configured for VoLTE.  But since the phone is still being sold, unless for the T-Mobile network, should work.  And I don't see any disclaimer on their site.

Thanks for the info - you are very helpful and I appreciate it.   I will check that out tomorrow when their office opens and look at the phone config.