I didn't use delivery confirmation (guess I learned my lesson), so I'm not sure what else they can do. I've known our mail carrier forever -- used to teach her kids in Sunday School. I've been trying to catch her when she delivers our mail. I know she would be willing to look for it in the office, but with the extra holiday mail, her delivery schedule has been all over the place. I really don't think it is at my PO though. The building is so small, I don't see where it could be hiding.