This is a fan forum, you're going to want to contact a-net. If you didn't do anything wrong then odds are your account was hacked and someone else did some botting or gold selling our something. Good luck.
As pointed out, we're a community forum, so we won't be able to answer that question. And you probably won't get an answer on the official forum either. The only way to get any information about why your account was terminated (and if perhaps you weren't careful enough and if it's possible that it got hacked, in which case there is a chance that you can get it back) is by creating a support ticket, on the link that StacyX provided. I hope you manage to sort this out.