What can I do about my post office's failure to deliver mail?

Were it me, I'd go in with some other affected parties & get a cellular-capable GPS package tracker like this http://www.globaltrackinggroup.com/gps-tracking-device-ubi5000e.cfm, then mail it repeatedly to the parties involved, being sure to retain the tracking data for each mailing. ...then, with that in hand, confront Someone Important. Or the local news, whichever. Also note, the device might never make it back to you, but that's why it has to be cellular-capable -- you can track it and confront the supervisor (or PostMaster, or whomever) saying, "If there's no problem, then why is the package currently sitting at (location), rather than my house, which is where you say it was delivered?"

When this happened to me, I got to know my carrier very well, and then I got to know his boss, and his boss's boss, and then I got the phone number of that person's office and I called very often. My calls and complaints to the 800 number went unnoticed, and my local Congressional office wasn't very helpful. But calling the manager worked wonderfully well. Turns out my local station was where "bad" managers were sent, until they could redeem themselves. Getting my mail to me in a timely manner was repaid by my sending letters about how great that particular manager was. And I tip my carrier at Christmas, too.

I second contacting the postal inspectors - they are a serious bunch. It sounds like your property is being stolen, and theft of the mails is serious business.

My bride notes that when we've had mail problems, a call to our congressperson has always netted an immediate response from the post office. Note that your congressional person may want detailed info from you.

You don't live in Chicago, do you? (There are a few documented black holes there, and I believe also in Brooklyn.) Normally with the post office I say, write the postmaster first, sending the letter via certified mail with electronic return receipt. Don't send it from that post office, either. You would be well within your rights to start a postal inspector investigation, and it sounds like it's bad enough to skip talking to the postmaster. I think Maxwelton's suggestion of contacting your representative is also a great idea, especially if multiple people in the area do the same. Be prepared to find out that someone, probably a carrier, is taking the mail for everyone, and either hiding or dumping it. The fact that the mail is described as delivered strongly indicates it is your specific carrier or someone in the office who is able to close the loop when delivery confirmation/tracked mail comes in. However, this kind of investigation takes time. http://www.oregonlive.com/pacific-northwest-news/index.ssf/2013/03/disgraced_former_mail_carrier.html http://www.gainesville.com/article/20091217/ARTICLES/912171049 tell of just two carriers who were caught burying and burning thousands of pieces of mail. It took years before people caught on, and then additional time to plant and prove that they were stealing mail. I hate to say this, but maybe you and your roommates should consider paying for a private mailbox in a nearby town. You can also have packages delivered to a workplace in many cases.

Have you talked to your area's post master? I would call the local office and ask to talk to him/her—that was my brother's job and he got phone calls on that more than once. It's their job to handle just these types of situations.

Go up a step from the local post office branch manager --- I'm not sure exactly who that would be, but try www.usps.com. (And it sounds like the problem is the specific mail carrier working the route that includes your address; check with your neighbors to confirm if this is true.)

Definitely call the post office and it sounds bad enough that I would contact the local Congresscritter as well.

It might be an issue with one carrier - every now and then you see a story about a mail carrier going to jail for something like being found with a house full of undelivered mail.