As far as i'm concerned, BBoy's post answers this thread.
Obviously if you wasn't doing it (your schools wifi doesnt make you change files lol..) then you got caught in someone elses ban.
Since you can't really prove you WASN'T the one doing it, you'll just have to avoid use of your school's wifi.
Let's just assume it is a good thing and that you now have some free time to do some SCHOOL work