It happened to me with my beautiful Pinball Magic I have up for sale now. Had a deal worked out after answering multiple questions and then got the vanishing act when I asked for payment. I'm just glad it didn't cost me a deal with someone else, which could very well happen.

I think sometimes people mean well and are all excited and then after a deal is agreed to, they start think about the money and get nervous and are embarrassed to let the Selle know. OR, maybe they agree to a deal and then tell their significant other and that ends the deal. Again, they feel embarrassed and just vanish.

My advice, if you decide not to buy a machine you agreed upon with someone, that's fine. Stuff happens. People change minds and that's okay. Just have the courtesy to let the seller know. Mho anyway.