Phone calls going right to voicemail

For the last 2 weeks - when I try to call my husband, the calls are going right to voicemail (our lines are on the same account) he gets no notification and it doesnt show as a missed all.  The phone is NOT on silent, it’s NOT on do not disturb, we did *73 , he has NO blocked contacts.  This is a real issue b/c I was in the hospital away from home and I could not reach him.  We even upgraded to a new phone (since his was several years old) and it still isn’t working.  I am really frustrated and debating terminating with Verzion since no one seems to be able to fix this -