Missing Emails in Outlook 2003

We ran Outlook 2003/Exchange 2003. One of our staff lost all her email in a specific folder under Inbox. This file is pecified by sender’s name, and recently the sender change her email address. I cant find the email in Deleted Items, even when using Recover Deleted Items. However if I use Find and Senders name, I can see all the emails her her activities. If anybody can help me find all these missing email and restore it it would be very much appreciated. Thank you.