She'll get hers...don't worry. I say follow through on the dispute. I would care less if she already has two strikes against her. That just goes to prove how careless she is on eBay. From the way she's been talking to you, I bet she never even SENT her payment. I just don't have time to deal with people like that. I wouldn't talk to her anymore. Block her e-mail, block her account and ignore her. Finish the transaction, close it and I would definitely leave her negative feedback. If she responds in her "all caps" childish behavior, just stay calm and professional. Trust me, people that deal with you also want to know how you handle yourself in cases like this. If you need to respond to her, just state the facts and leave it at that.
BTW...in your auction, when you filled out the selling form, did you only mark US as where you will sell to? I'm just curious how she managed to find your auction if that's the case.
You might want to leave her eBay ID in the feedback forum. Even though she's on her way to being booted from the site, it might be good to know.