I only noticed this thread now. And I am really sorry to hear many of you are having so many troubles with her... =/
I sold her 2 nirvana ponies as well earlier, but she was only late about a week or so from the time when she was supposed to pay the whole sum, so I ended up having no problems with her. And she did not make a paypal claim from the money after she received the ponies, so I am sure you will be fine in this regards Willa. But certanly if you know you can't afford something you should not be making promises to many different people about byuing things... =/
*hugs* Very sorry to hear from all of this.