So let me get this straight: you did not complete any deal with him because he wouldn't bend to your demands to do what you consider to be a secure transaction. Is that correct? And yet, you feel entitled to brand him as a "fraud" and a "scammer" without giving him the benefit of the doubt?
Unless I have misunderstood your post, I believe you are seriously out of line. Any seller is free to choose the rules under which he is willing to complete a transaction. Given these constraints, any buyer is free to abide by these terms or give up on the deal. Just because he declined to agree to your own terms doesn't necessarily make him malevolent or untrustworthy. And it certainly shouldn't expose him to libel from someone like you.
Feel free to correct my perception if it is false or incomplete, but I am genuinely shocked at your inquisition-like haste to demolish one man's reputation simply based on your perception of what should be acceptable or not.