I once bought a book from a 3rd party seller on Amazon. I was notified that it shipped, but never got a tracking number. I waited..and waited..and waited...three weeks went by, no book. I contacted the seller, and got an e-mail back stating that they'd discovered that their local post office had been mishandling packages and mine had never been shipped once it got to the post office. They assured me they'd rectified it and I'd be getting my book shortly.
I thought that was a weird excuse, but hey, you see stories all the time about postal workers hoarding mail, so it might've been true. So I waited, and waited, and waited..and another 3 weeks went by. I e-mailed the seller again, feeling extremely irritated, and told them if I didn't have the book within 4 days, I would be filing a complaint through Amazon.
I get another e-mail back from the seller stating that their own employee had been the one hoarding packages, and that employee had made up the post office story and they'd only just found out about it. They'd ship my book "if they could find another copy of it" (it was an out-of-print book).
No offer of reduced shipping, discount, or expedited shipping.
I finally got the book another two weeks after that.
I left the seller negative feedback, and they e-mailed me with a sob story about how it wasn't their fault, it was their lying employee, and my negative feedback was out of line and I was ruining their feedback score.
I didn't answer, left my negative feedback as it was, and never bought another book from that seller again.