Haven't been able to get voicemail notifications since phone has been new (over a year). Went into "voice" in apps and changed the battery to unrestricted and restarted the phone and it still does not show notification for voicemail. When I go to the "phone" app and go to notifications the "allow notifications" is greyed out and I am unable to change it. When I go to "notification categories" both missed calls and voicemails are greyed out. How do you change that?