Visual Voicemil app not working, but voicemails available in Phone app

I have issues with the Visual Voicemail app for about 3 years. First on my last phone (S22 Ultra) and now on a Samsung Galaxy Ultra S26. I've had Xfinity Mobile service since June 2017 and am now on my 3rd Samsung Galaxy phone. And I currently have the Premium Unlimited service.

What happens is the Voicemail app just stops showing all new voicemails coming in. It seems to do this every few months! It will show the older saved voicemails though. In the past I have followed a set of clearing cache-data/resets/restarts etc to finally get it to work again, showing the new voicemail message also. But this time that did nothing at all. Nothing else has made any difference either.

The Visual Voicemail simply says there are NO messages even though there are new messages. And no one has an issue leaving a voicemail.

But in the Phone app itself it does show the call coming in with the voicemail recording icon.

And if I select that call it shows there is a voicemail of whatever length. If I click on the microphone icon on the right then it will play the voicemail!

So I have several questions:

  Is this a Xfinity Mobile service issue or a Samsung phone issue, or both?

  Is the Visual Voicemail app worthless?

  Should I just listen to the voicemails in the Phone app itself because that is the ONLY reliable method to get to them?

Also,

        the phone OS is fully up-to-date

        all apps are up-to-date

        the phone has been restarted...many times in troubleshooting this...

        I have  full access to towers for mobile data and full access to Wi-Fi

        I do not use any VPN on the phone

Thanks