Why Was I Banned When I Was Asleep???

Last night I was farming some wool cloth on my 26 hunter troll, I left my computer on and laid down for a few moments of rest. Needless to say it was a long day and I fell asleep after a little while. But when I awoke and went to play I was logged out and on the login screen. I entered my username and password and it turns out I was banned! I went to my email and they said I "Abused chat privalges and advertised" I never did any of that. I was asleep at the time of the banning. How could I have possibly have done it. Please I don't want to seem agressive but I didn't do anything that violated the user agreement.