I'm dealing with the USPS now on a kit they have lost. From AoA. Tracking says it was delivered and signed for by me. Never happened. Waiting on an update and trying not to lose my patience.
Had the same situation couple months ago, but it was just some small parts (pins, etc.) that were listed as delivered and never was. Checked my security cameras and noticed the USPS van drive down the street around the alleged delivery time, but never stopped in front of the house nor any postman come through the gate. WTF? Went to the main post office and pitched a bitch. Was blown off and told to get ahold of the afternoon supervisor. Gave the info to the supervisor and he tells me he'll have to speak with the carrier assigned that day. Don't hear jack shit for three days and decided to check the neighbors. Sure as shit two houses down the padded envelope is in the neighbors mail box. Never told the shift supervisor I found it. Wanted to see if this clown ever followed up. Call him about a week later and had to "refresh" his memory. He tries to run the tracking number four times with no info coming up. I ask him if the system purges itself after a few days when something is logged in as delivered. He tells me that he's been able to find stuff still listed in the system six months down the line. While I have him on the phone I grab the laptop and run the tracking number and sure as shit it's gone---no info! The supervisor tells me he can't do anything until he has a good number and I should get ahold of the shipper. It's the same number I've run with no problem written on the same piece of paper from day one. Personally, I suspect the supervisor wiped it out of the system than call one of his bro out on the carpet.
Good luck, I hope things work out for you. I don't trust the people here as far as I can throw them. Typical example of the type of people working here at the post offices: Walked into a branch nearby one day and couldn't believe it---the smoke from the weed they were smoking in the back was so thick you could cut it with a knife, as the saying goes. No, it wasn't some asshole that was smoking "Loud" in line in front of me. You could see the haze! It was ridiculous. No point in even mentioning it to the person behind the counter since they were probably well aware of it. Disgusting.