I've had this happen plenty of times. I think sometimes they find a better offer, sometimes they're just being rude. I actually think one time a dealer got a better offer. Talk about poor service - We had worked out a price after several days and several phone calls. They actually faxed me a credit card receipt to sign. When I faxed it back signed, just a few hours later, they told me, "Sorry, our mistake. That unit was sold over a week ago." Either they put it up on auction (where I first saw it) on Audiogon AFTER it was sold, or they got a better offer and pulled the plug on our deal. I know it sounds cynical, but I think they got a better offer, and I think that happens with private sellers all the time. People don't respond cause the unit is sold, or they stop contacting you after you've agreed cause they got more from someone else. It's just the breaks of buying used. Fortunately the effort involved in doing this really pays off in the end.