I know exactly where your coming from mate, people like him are a waste of space, i had a similar thing few months ago, forked out £300 for a cyclinder head that was duff, was ignored etc etc etc,
I wrote an essay on here about it, and yes you do get some positive replies, but such is life you still get people like above who seem to take the other side just to be different!
My advice to you, not saying its what id do , i had alot of evidence , bank transfer, abusive emails, texts the item itself! so court was the only way forward, the other way is a full tank of fuel, a couple of friends and an address!
Dan