Galaxy A50 Not Compatible After Android Update(?)

   I have been using an A50 with Xfinite Mobile since Sept. 2019.    Recently, the phone would not dial; the phone displays either a "mobile network not available" or "not registered on network" message.   Worked with XM support and they stated per the IMEI, the device is not compatible.  I verified their statement with the XM IMEI look-up link.  There was no explanation why or how the device could suddenly become not compatible.

   There was an Android software update was installed on 04/10/2020 which is around when this problem started.

   How can I get the phone restored back to being compatible with Xfinity Mobile?