Since we have had an influx of negative feedback issues in the last two days, here is a short education course on what warrants a negative feedback.
This is what warrants leaving a negative feedback... A deal must be made and agreed upon, such as a place to meet and a time and what day. Now if one of the parties flakes on the deal, this is a time for negative feedback. However, give the other party sufficient time to explain himself, maybe an emergency happened or what not. This has happened here before and both parties ended up getting the deal done.

When leaving negative feedback, be sure you have all the saved documentation to prove a deal was in place, in case you get retaliatory feedback. I suggest email or pm only. When you contact a mod about it, send all this info with a description of what happened. If you dont have the info, dont waste the mods time and plan on being shit out of luck getting it removed.

Here is some reasons NOT to leave negative feedback and if left, may get you a vacation:
I sent pm saying I will take it and sold to someone else
Member lowballed me
Member thread crapped on my thread
We were working a deal and he sold it to someone else.

Here is the link to the feedback in the reference section, I suggest everyone read it, this will save you headache later.
SGN Reference Section