ghost user in exchange/AD

I have a user that added the receptionist as a delegate to his calendar. The idea was that the receptionist would get all of his calendar appointments and manage his calendar for him. Problem happened when the receptionist left the firm, the normal protocol was followed to remove that persons AD and the email and mailbox. The issue now is that when someone sends that initial user a meeting request the sender gets a NDR from the receptionist account (the user still gets his meeting request). The receptionist account isnt listed as a delegate in his outlook, or in his AD account. How do i remove the receptionist references in his account?
Server is Windows Server 2003sp1, Exchange 2003sp2. Client is WinXPsp2 with Outlook 2003sp2.