But have you found anywhere, I mean anywhere that it says that the Post office is required, by law, to deliver to your door?
You won't because it doesn't exist. No matter how bad you it want to, it doesn't.
Trust me, it's been looked for by the NALC in attempts to create routes.
Your problem was caused by your neighbor. You need to deal with your neighbor and talk it out with them.
Leaving a 3849 in your box out at the road is a perfectly acceptable form of notification in your situation.