I just received my new iPhone 4s (previously using Droid Incredible) in the mail. I am not that tech savvy, but managed to activate the phone and have been using it for a couple of days. However, I am not getting voicemail notifications. I went through the settings and have an alert selected and am using the default greeting. My sister has left two trial voicemails and I did not get notification for either. I was able to call my voicemail and easily listen to her message. Any tips? Thanks!