I have played against some aimbots myself. Like you I also have proof of their cheating. Like you as well I have filed complaints. Sadly, nothing has happened to them and they are still playing and still cheating. The guy even had the nerve to place the video I made on his cheating in his file share.
I also posted in the forums just like this.
However, I recieved a warning and nearly got banned for placing it here. It seems this is not the place to complain about cheaters.
While I was busy being yelled at the kid was still out cheating.