This happened with one of my packages once while I was away on vacation! It said "delivered" online so I had a friend go to my house to pick it up because it was winter and I didn't want it to get damaged from sitting outside. She and her husband looked all around the yard and outside of our house but couldn't find it. I was seriously panicking that it had been stolen or something! Finally when I called UPS we got to the bottom of it and I found out it was at the PO and would be delivered with my held mail when I got back. Whew!