I'm afraid he's not breaking a rule playing lower rated players all the time... If that's the way he wants to get a high rating I guess there's nothing we can do about it.
Where/How do you report someone exploiting the rating system

Uh, thats not the problem. I guess my title was unclear. He has only played one opponent and that opponent has conceded every single game on turn 4. Pretty obvious case of collision (or is the word collusion?).

The guy that sinir123 got his points from also got his points in a shady way. He's got a bunch of short games against the same player in his game archive.

Here is a link... if you look at his live chess he is 983 after two games but a 2000+ CC... yep, something fishy going on there...
http://support.chess.com/index.php?_m=tickets&_a=submit
B
Ie: http://www.chess.com/echess/profile/sinir123