Sometimes it can be the final delivery too. I get stuff from the carrier that Squadron uses all the time, and from time to time, they change drivers, or have one fill in, and can't, won't or try to find me, and mark it as undeliverable. And believe me, I'm not that hard to find, just follow the directions. I also opt to have my phone number on the package notes, but that doesn't mean that the driver will call.
As for problems with Squadron, haven't had any, other than not putting something I really want on sale
Henry