You dealt with it in the right way (leaving this kind of post in this section); some would say that you shouldn't leave "retaliatory feedback", but the truth is "trust feedback isn't moderated", so it has to moderate itself.
I got one from him too:
You should learn to worry about yourself and stop cyberbullying others online.
which I just ignored.
If you look at my trust feedback page, or pretty much anybody who's been around for any substantial period of time, you'll notice that they probably have some b.s. negative feedbacks. His feedback is not part of Default Trust, so it won't show up as Trusted Feedback. He also didn't leave a reference. In short, nothing to worry about.
I have opposed his
flag on your account.