The way I see it is that all you have to do is 
tell her: "You didn't use Buy-It-Now."  She knows 
she didn't, she's obviously just playing stupid 
to see if she can con you or pressure you into 
giving her something for free.

Of course, the *first* thing I would do is to 
deny her payment - or send it back. Then there's 
no way she can claim she paid you and you didn't 
send the item. The second thing I would do would 
be to send copies of her threatening e-mails to 
Ebay so you have *that* on file with them.

It's amazing that someone who claims to be too 
dumb to understand the concept of Buy-It-Now, has 
no problem understanding how to file complaints 
against someone. Methinks maybe they've done this 
before??

Many Sharp Smiles,
--Drac