That vendor has been banned so it has in a way been resolved even if that doesn't help you recover the loss from being scammed. Regarding your question re how to report people like this there are a number of options, hitting 'report vendor' is one, submitting a customer support ticket alerting the admins is another and posting here on the forums is a third. Personally I would recommend doing all 3 when you observe shady behavior and/or suspect a scam and any vendors names getting a few mentions here will result in my passing them name up for an audit.