Ebay Issues... (update)

I've usually had good experiences with ebay, but lately I've been cursed with several bad big transactions! The current one that's bothering me is for my 1972 VW Bus. I sold it on ebay late february. The high bidder had low feedback, but I contacted her first, and everything seemed fine. She said she was very serious, and hoped to win. She did, and sent the $250 deposit the next day. I talked with her, and everything seemed to be going well.

A few days went by, and the day she thought she could come pick it up she didn't show. She called the next day, and apologized, and said she would keep me updated. She said she was waiting for her tax return or something, and that it hadn't come as early as she thought it would. That's the last I've heard of her. Meanwhile the Bus is still here, and I have to get it sold! As per ebay rules, she's technically required to pay in full within 10 days (it said so on the listing). I finally decided to relist it after opening (and closing) an unpaid item dispute. I opened one, and waited the necessary time, and am about to close, except now apparently she's opened an "item not received" dispute against ME, saying she's paid and hasn't got the item!

So frustrating! She's made no form of contact and hasn't responded to many efforts from me (calling, email, ebay messages). I think she now wants her deposit back. I still have the seller's fee, and all the time wasted and the loss of other interested buyers. What do you think? What would you do?

UPDATE: Things have gotten weirder.. After looking into the unpaid item thing (also on paypal this time), I found a message from her. Here's what it says:

"Talked with the seller's mechanic, and was told that automobile was not at all as represented on ebay. Seller sold me this vehicle, KNOWING that I had over a five hour drive home with a child along with me, and still never mentioned all of the many problems I might have ran into driving home. I was lied to and have no vehicle to show for it. I have talked with an attorney and fraud detective in both my hometown as well as in Laurel Md, and will proceed as necessary if this cannot be handled here."

Needless to say, I'm confused! I never gave her the number to my mechanic (and he's a backyard mechanic so she couldn't have just "found" his number), and he certainly wouldn't have told her it's misrepresented! Nothing's guaranteed as it's a vintage vehicle, but it runs great and nothing needs to be fixed right now. Not to mention she's the one who wouldn't communicate or respond to me! Is this real? Or some sort of fraud? I've talked to this woman over the phone once, which makes me think it's somehow a misunderstanding, but I don't know. The mechanic thing really throws me off...