I appreciate you continuing to work with us on this, and I want to make sure we are pulling out all stops to see that it is addressed properly. Since this is not a known issue for the iPhone XR and we have confirmed both your device and the app itself are up to date, I want to explore other potential root causes.
Your screenshot clearly indicates that some kind of software error is behind this. When were you last able to access the My Verizon app on this device (if at all)? Were there any changes (other new apps, or updates to existing ones) you may have made around the same time? Keep in mind, we are not referring to My Verizon itself, or the iPhone software, as we have already reviewed those avenues as potential culprits.