A few years ago I also had a package show as delivered, but it was not delivered that day...It was a one of a kind Nebraska Indians cabinet photo and I immediately called the post office to have them track it...they told me it had been delivered....I asked them to contact the mailman, and they did, he claimed he delivered it.....I asked my neighbors if they had gotten it...nope, none of them had gotten it. So I called the police to tell them I had a package stolen...the police showed up to my house and made a report. A few hours later the mailman delivered it to me. I have no idea why he lied to post office about delivering it. It was not my regular mailman, but a sub.
I called the police to let them know it was delivered and the officer told me that he contacted the mailman at which point the mailman suddenly found the package.