This might be a bit late, depending on how urgent your issue was, but depending on how many days your exchange server keeps messages for you may be able to recover them. You'll need to search google for how to restore deleted mails on exchange, particularly look for the ones that indicate a registry fix to enable other folders. By default you can only restore deleted mail from the deleted items folder, if you have shift-deleted or moved to another pst file then you need to make the registry edit.