I don't know what that picture you linked to has to do with me, or even what it is.  Looks like a conversation between two people, neither of which is me.

You ought to look up the definition of "blackmail", because me leaving you a neg for trying to sell an account is not blackmail.  If I were to ask you for money to remove the feedback, that would be extortion I'm pretty sure, but I haven't done that.  It's OK if you leave me a neg.  Lots of people have done the same.