I'm so sorry this happened to you. I work for the good ole PO and I must say it's very difficult to eplain to customers why these things happen. Could be the address was wrong or not readable on the machines, the zip code wrong or maybe the wrong postage or just plain old human error by a postal employee. Working there for over 31 years I've seen my share of what can go wrong, there really is always an explanation. Did you ever contact the PO where it was delivered to see what they had to say? Also you didn't say how you mailed it...first class, parcel post, etc. You always hear of the "one" piece that didn't get delivered and never all the rest that do get delivered on time (like your bills...lol). I'm so glad that it was found and delivered because trust me, the one thing the PO wants to do is deliver the mail as quickly and proficiently as possible. Delivery Confirmation is a good way to track what you have sent, but if you have had good luck with sending your packages by any other means you should continue to do that. Don't let one mishap persuade you to spend any more money than you have to.