I recently upgraded to the new $30 plan w/$5 monthly discount. Was
having issues with voicemails showing up late and not getting notified
that I had a vm before the upgrade. Then the voicemail app stopped
opening altogether. This fixed it for me: Go ...
You don't say what problem you are having with voicemail. If it's that
visual voicemail is no longer opening this is what I did to fix it: Go
to Settings - Apps - Voicemail - Storage - Clear DataThen Open Voice
Mail and go through the prompts .