Disappearing Email in OWA

I have a user who travels amoung our different sites, he uses Outlook Web Access to get to his email. This user has been accessing his email in this way for about 6 months now. This past Monday the user was checking for a message he was expecting by pressing send/receive. His new messages were received but approx. 14 pages of messages, representing the last 2 weeks of mail disappeared. I have logged on as the user with Outlook 2K to check the restorable deleted items as well as to check the outlook today folder for storage. The messages do not appear to be on the local machine either. Any suggestion on how to get these messages back?