Hi John,
Your system is UC520, so I guess you're using the Unity Express for the AutoAttendant. Check if the script that is uploaded in Unity Express in the menu option is sending the calls to the correct extension, you can do that by downloading the script to your computer and opening it with the CUE editor. You can download the CUE Editor from this link http://tools.cisco.com/support/downloads/pub/Redirect.x?mdfid=278535672 , click your Unity Express version and after that choose Unity Express Utilities.
If you need help with the script post it here so we can check what is inside.
Gabriel.