Getting USPS to care is impossible. I actually got a reply from Jeff Bezos in addition to a "?" email because Amazon was using USPS on Sundays for delivery, but USPS is unreachable on Sundays and Amazon has no way of contacting them either, so when USPS deliverymen refuse to deliver packages to my very obviously open business on Sunday citing that we weren't there (bullshit), there's nothing I can do. I wrote it up, sent it to Jeff, and they blacklisted USPS for my route on Sundays and now use Amazon drivers.
Unfortunately, if you go through USPS, they don't care. Much like any other government service you use.