Important thing to note is that if you feel you have been wrongly banned, make sure to contact them. There have been reports of it being reversed upon further review. Hopefully, this also means they have done all the bans they are going to do for now, so if you still have your account you are probably safe.
We want to emphasize that this action was not taken lightly, and was only done to address the severity of the problem. Win trading goes against the spirit of World of Warcraft and hurts enjoyment of the game for all players who earn their victories by competing in a fair environment.
Blizzard Entertainment has always taken a very firm stance against win trading, and additional in-game updates will be made to limit this abuse in an upcoming patch. Additionally, we will continue to closely monitor the Arena system for any signs of win trading or other abuse.
If you were among the players actioned for win trading, but feel it was done in error, please contact our account administration team at WoWAccountAdmin@blizzard.com.
Thank you for your support and best of luck to you in all of your games in the Arena.