Voicemail Notifications

I recently switched to xfinity mobile and purchased a new Galaxy s10e and a Galaxy A50.  I am not receiving voicemail notifications or missed call alerts on either phone.  If I manually check the apps, I can listen to voicemail messages.  All notification settings are properly enabled, including app icon badges.  I spent over an hour on the phone with tech support. He was unable to solve the problem. He said he would research the issue and call back, but never did.  I drove to the xfinity store where I bought the phones.  I got no help there either.  Is there a fix for this issue, or am I forced to choose between manually checking voicemail several times a day indefinitely, or switching back to Verizon?