@apaterson,
If you go to USPS.com and click on "customer service" it will bring up several options.
Under the FAQ's you'll find one that says "What if my USPSĀ® mail/package has not been delivered?" Click on the link there that says "Answers".
From there, click the link that says "Delayed mail report" and fill out the form.
I just did that a week or so ago and they got back in touch with me the same day and I had my mail two days later.