Not a bad idea to restrict people from using the site to dump machines and run.
At the end of the day, it is the sellers machine to do with as she pleases but it is bad form to ask for a certain figure, which she was going to get, then hear of a chance to get a bigger price for it, back out of the original deal then accept an offer for more $$$ from the same person then back out again when the lure of eBay is too great despite saying quite clearly the machine would not be listed on eBay and arrangements were made to pick up the machine and the increased offer was accepted.
I'll say no more and best of luck with the auction.