Send a email to support (email@example.com) to appeal your ban.
Okey, but why more then 5 my friends got banned for nothing?
Duplication bug resulted in lots of Byte Coins being in circulation. Any person that had one of these duplicated Byte Coins was issued a ban.
As RetNos said, send an email to support with information like your in-game name, when you saw you were banned, and any other information you may think would be helpful. Remember to be respectful within your email.