Sounds like you ganked a GM's player character lol; tell them Blizzard has PUBLICLY stated Multi-Boxing 5 characters is 100% legal and if they don't provide evidence otherwise you're gonna throw a major Customer Service Forum shitstorm and chances are they'll be reprimanded for opinionated and instant final bans.

Speaking of Final Bans, why are they instantly perm-banning you? They usually go with 3 strikes and you're out...72hour ban, few days ban then permanent...and that email says stuff about exploiting the economy rather than pvp-related GM's opinions so it makes me wonder if this is really the reason you're banned...just gives off a whole "VAC Forums - I was banned cuz my brother was on my acct and must've downloaded cheats!" vibe, no offense :p

Edit: And funny you should word your post like that Keyclone...I've got a post coming later tonight after I get home and have access to youtube that's related to that ;)