I know all too well how frustrating the USPS can be. A few years ago I ordered some clothes from Kohls and the day the tracking number said the package was "out for delivery", it never showed up. That's sometimes happened and I'll get the package the next day. So the next morning I check the tracking number and it says it's in JACKSONVILLE. What?! So I try calling my delivering PO to see what the heck happened and the phone was a constant busy signal (tried calling several times). So then I tried the Jacksonville PO and they tried the "Well everything is pretty much automated so we don't know." But they took my info and said they'd try to find out what happened. In the meantime, I contacted Kohls about it and their customer service opened an investigation on their end as well. They ended up giving me a refund for the shipping amount. A day or 2 later the Tampa PO called and got me all confused. I got back with Kohls again and we both agreed the package was just lost in the mail. They offered to either give me a refund or send a new package of what I ordered (minus the necklace I had ordered as they showed it was now out of stock, and gave me a refund for it) and free 2-day shipping to my work address. I chose to get a new order because I wanted the clothes! Got the new package without an issue and to my surprise... included was the necklace (guess they came across another one)! I love Kohls.
I just don't trust my delivering PO because they mess up all the time. I get other people's mail in my box at least a few times a month.