Account Banned

Character Name: Stonéy
Server: PVP
Hey guys, so I just logged in and ran around booty bay a little waiting for my friend to come onto his alt to level with me (I only play with this guy, mostly around his house on my laptop) while I am waiting I just alt tab like usual, when I return to wow I log off to wait a bit longer. When my friend tells me he is ready to play I notice I have been disconnected from the server, upon trying to log back in I get the banned message? So I try to log into the website and it lets me know I have been banned, I'm not sure if your supposed to get a reason with this but I cannot see one? As far as I know I have not broken any rules.
Server: PVP
Hey guys, so I just logged in and ran around booty bay a little waiting for my friend to come onto his alt to level with me (I only play with this guy, mostly around his house on my laptop) while I am waiting I just alt tab like usual, when I return to wow I log off to wait a bit longer. When my friend tells me he is ready to play I notice I have been disconnected from the server, upon trying to log back in I get the banned message? So I try to log into the website and it lets me know I have been banned, I'm not sure if your supposed to get a reason with this but I cannot see one? As far as I know I have not broken any rules.