I got cheated on ebay!! Please Help!!!?

I mailed $140 in cash in payment for a 30 gb white zune and the person sent me an email stating that she received the money. After 2 weeks of waiting (October 23, 2008), I send an email inquiring about my purchase. She replies saying, "You should have received it last week. Let me check at the post office." Yet, I never recieved the zune. Now, it is three months later and I don't have the money nor the Zune! What do I do? I still have her adress, email, name, ebay user ID if that will help. The email that she sent me confirming that she got the cash is in my other email (which mysteriously got shut down/frozen by Yahoo) so I can't pull that email up. Please Help Thanks!!!!