It's annoying when that happens, too busy, can't see you til.....sorry, it's sold! Happened to me with a Bianco Fuji Gransport last year, I was gutted but at least the guy was apologetic and stated facts. When someone offers a deposit even with conditions attached, take it, simple. If you're not happy with the conditions then there's a reason to withdraw it from sale or sell to someone else. Reading between the lines, I don't think you've missed out on a good car, you never know, but it just doesn't seem right.
I am now on the case, I hope I don't disappoint in my quest.