Please help - unbelievable this please

Okay this is what happent: I start crossfire, I join Ship game, I got DC with disconnection error.
I start crossfire again, got disconnected again
Then I start crossfire again and I was able to join egypt game, but I had really high ping and that was already weird, but I did nothing and I moved and I got kills like multi kill and stuff like that, while I even didn't touch my keyboard or mouse. The things I saw was that a player with a different name made kills when I saw multi kills and stuff like that!
Now I'd believe that someone was playing with my account while I just watched it~!
So to be honest it's really unbelievable and I got a few screenshots of it, but it's not good prove. What can I do?!