I live in a city with a very rigid street-naming and numbering convention (i.e., even if you've never heard of it before, given a street number and postfix such as "14th terrace" is already enough information to know whether it's north-south or east-west running, approximately where in the overall grid of the city it's located, and what kind of street it is--for example all "lanes" are cul-de-sacs). The problem with that is the courier companies all come to rely on that system extremely heavily, and, luck of all lucks, the cul-de-sac that I live on was mis-named by the city as a "court" instead of a "lane".

Both of the big-name companies here (UPS & FedEx) give phone numbers on their tracking systems that you can call when they are unable to deliver a package, but a) nobody is actually notified of the failed delivery, so you have to know that a package is coming in and actively watch the tracking page to catch the failed deliveries, and b) the people you talk to at that number are either incapable of or unwilling to make any kind of permanent note in their system that can fix chronically failing addresses.

For several years we put up with about 80-90% of our packages failing delivery (moreso from UPS than FedEx, but both were pretty abysmal) due to "incorrect or incomplete address," being forced to notice this on the tracking system on our own, then calling to tell them that no, the address is not incorrect, the street itself is misnamed and yes we've called to explain this dozens of times in the past and can you please put some kind of permanent note in your system to ensure this doesn't happen anymore.

A couple years ago, after another failed delivery from UPS, I decided to try a new tactic and looked for public UPS twitter accounts that I could tweet in the hopes of bringing it into a more public sphere. I found @MikeAtUPS and tweeted him that another delivery had failed, it happens a lot, and nobody at UPS seems to be taking the situation seriously. He directed me I think to a corporate support email, which I followed up on, including links to the tweet and response. Amazingly, this actually worked. They responded immediately with an apologetic email, said they had made a correction in their system (though, I'd heard that one before), and that this shouldn't happen again.

And it didn't! After that, UPS stopped failing our deliveries (with the very odd exception). FedEx slowly started to get better over time as the drivers started to learn the area better, and also stopped being an issue. So maybe the lesson is, skip the outsourced help desk numbers and go public with your grievances if you want to be taken seriously.

As an aside, USPS has not once ever failed to deliver a package or even drop one off later than the expected delivery time. If it's an option, I will always choose them over the private courier services 100% of the time.