Fools with feedback

I had my first negative feedback over the past week, the guy seriously lives on another planet. First he messages me about finding a supplier for computer games and action figures - to which I actually did get some information for him, but he left the negative comment on the same day I received the information.

He also stated that some of the links are not working in the list he bought from me, and haven't been working since 2003! I can't understand this as it's based on last years convention - Here's the exact reply I sent on the same day.
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Hi,
Can you please send me the links that aren't working?
I'll have a hunt around for some suppliers of the mentioned
items you're after, I'll let you know how I go in the next few
days.
Regards,
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Then I contact him through eBay and ask him why he left negative feedback - I said that I'll leave negative feedback on his profile. He then does his chewy stating that I'm threatening him, and searches my facebook profile and tells me that I should stop posting insulting comments on websites! LOL anyway, there are ways that i'll be dealing with this, the great man Donald Trump says "if they fuck up, make them pay" (paraphrasing again). The only reason I'm taking the time to write about it is because I know he'll probably find it, and then write a sad and very long email like he's done about my facebook update.