I agree with others here. Just take the negative feedback
and move on. I got my one and only negative feedback two
years ago in much the same manner. I bought a set of 3.73
gears and they came in a box ( only loose paper stacked
between the ring & pinion ) with totally inadequate packing for a
set of precision machined gears. I got pissed because the
seller was a long time seller and should have known better.
I left the dirtbag neutral feedback and he left me negative
feedback. Talk about inappropriate! I contacted eBay and
they did nothing.
As was suggested, others will see your feedback history and
can figure it out for themselves.
BTW, the billboard sounds appropriate, but that would most
likely get you on the bad side of a liable suit.
Steve