Thief...

[shilala]

Joe, You have her name and address.
Use Zabasearch or any phone number reverse address seach and give her a call.
Be courteous. It could be a simple case where her email is down, etc. Use that approach very cautiously and with the utmost respect.
Once you've gone that route, send a certified letter explaining your intent to contact the authorities in her area, naming her local police department and the head of that department (who you should have called before you write the letter).
I've owned an online auction since '99 and have dealt with hundreds of these sorts of things, usually to the satisfaction of both parties.
Usually it works out if you do things just right.
The key is to be very polite, extend the courtesy that it's an honest mistake, and do not make threats.
When you write the letter, don't threaten at that point, either. Simply explain you're going to ask the local police to come and speak to her.
Usually a police officer will stop by and speak to her.
At that point, the problem is usually solved.
Hope this helps!!!