Can i get unbanned from COD4?? (Read description before flaming)?

I was playing COD4 and my crosshairs went. Got annoyed and googled/youtubed everything, spent days trying to get them back. Eventually somebody offered me a crosshair file that he said to put into my COD4 directory, obviously i was a fool and fell for the whole thing and i got banned for hacking... anybody help please :/