Weird things going on with our mail delivery

Two weeks ago we got a piece a mail that was sent 5 months ago. I thought it was a one time fluke...but...

Today, we got more interesting things in the mail. Including the following items:

- November 2007 issue of a magazine
- item postmarked on October 18, 2007
- item postmarked on August 15, 2007
- July 2, 2007 issue of a magazine
- item postmarked on June 4, 2007
- item postmarked on May 19, 2007 (something sent over 1 year ago!!!)

I submitted an inquiry via the US Postal Service's website. I'm very curious as to what's going on with our mail!