If you got banned by the automated system, then you had to have said some pretty bad stuff in chat, which is a violation of our rules.
If you do not agree with a ban, you can put a customer support ticket in and they will review chat logs.
You could be getting chat banned by players as well, enough reports will get you a chat ban.
My suggestion, perhaps either disable chat, or pick the words with which you use in chat better. Be respectful and courteous and you won't get chat banned.
-Hapa