GMs are human, therefore they are not infallible. They do make mistakes. Follow the directions in your e-mail, which likely says to appeal through accountadmin@worldofwarcraft.com

If you do a search for "unbanned", you'll find a couple others who were mistakenly banned for one reason or another, and were restored after they appealed and were re-investigated:
http://dual-boxing.com/forums/index....light=unbanned
I got a email this morning saying that multiboxing was allowed and they apoligize for any inconvience and these two GMs will be taught about multiboxing so this dosen't happen in the future...

So all in all i got banned, then talked to a bud, unbanned and a apoligy... Just a wierd experience all together...
http://dual-boxing.com/forums/index....nned#post85631
lol, so they gave me my account back and said that keyclone is a legal 3rd party program. sigh, i love blizzard. Must have been some new admin or something, idk.
Also, be sure to do a scan of your computer for any viruses/keyloggers. It is possible you were banned when it was really a hacker in control of your accounts. Granted, I find this unlikely because you mentioned a trial account -- and there's restrictions on trial accounts -- but it's possible nonetheless.

In addition, I've also reported myself back when I first started multiboxing, to let the GMs know that I was a multiboxer and to ask if they could put a flag on my account so other GMs would know as well. Since then I have never been whispered by a GM (unless I ticket them first) and I know I've been reported a multitude of times.