My iPhone 5c is supposed to show me on the main window if I have a missed call or a voicemail was left. At times it will only show me a missed call but won't show that a voicemail was left.. This will go on for days unless I shut down and restart the phone. As I don't usually shut the phone down I miss voicemails as they do not show up on the front page or on my voicemail notification box when I have my phone screen open. Why does this happen? I have been embarrassed by being days late with replies or call backs.