If you don't know who he is then that is another warning sign.  Why not just post something that looks like proof and people can pm you for more details.  You have a good idea here trying to sell your account, but you have executed it all wrong.  
You've got to post a heck of a lot more details to get people's interest.  

Ok I re-read your first post again and the only line that sounds fair is the last line where you say you are angry already.  I suggest editing that post and posting the screen shot you talk about with the important info blurred out.  That would be a step in the right direction.  Also simply sending someone your passwords doesn't guarantee them ownership in anyway.  You could simply log in yourself if it ever comes back and empty the account yourself. 

Can anyone think of a way to guarantee this kind of sale?