This is not "one chip deal gone bad." A thoughtful analysis of the evidence shows a clear pattern of malintent. It's clearly the "fear of a negative" that allows people like this to still have a 99.3% positive rating in 784 feedbacks. When you have a good transaction, it's appropriate to leave good feedback. When you have a transaction like I have had, the only responsible thing to do is to leave a negative. Otherwise, what's the point of feedback?