I looked at your history and I see that you played two games with that user, one win as black and a loss as white. Are you sure you didn't play him twice?
yay
yes, I was black, the first game. If you review both games you will see they are exactly the same game, just the colors are different where he made himeself black and me white.... It is the same game. The first one I won as black... then he copied the game and put himself as black and me white, changing my score and maintaining his rank....

love and peace