Could be a couple of things, but the guy only signed up on the 21st of Feb this year and has made only 4 posts. He also lists crescent city as his home address, which got swamped during the tsunami.

But if you haven't received payment yet you are most likely screwed for good reasons or bad.

Assuming you did not send the item(s) before payment was received.

I would send a PM to that member letting him/her know the deal is past the point of reasonable time given to pay, and as such the deal is voided due to inaction on thier part.
Then I would re-advertise the item(s) here.

But if you sent the items before being paid?
YIKES!

As an aside: I never send items without tracking these days.
First off it is freaking CHEAP!
Second: things get lost.
People forget... or they were not the person who took it off the porch (mailbox) whatever...

From what I have read looks to me like you have gone out of your way to be as generous as possible.

I would have already been done with that potential buyer and moved on.
I applaud your patience.  
My wife always chides me that it is a virue....
One I dont have...