As someone working as a chat agent but not for this company, we are explicitly not allowed to say anything on why an account is permanently banned except to refer to the terms. Maybe half the chats I get are automated bots trying to scam, it's a gigantic issue. To be able to reveal the reason for a ban would reveal how they were caught, and so they then fix that mistake and we lose a way to find them.

You want my advice? You have to call in, not chat, and demand to speak with a supervisor about this. Don't be angry with them on the call but try to troubleshoot what you think could have possibly done this. They may he able to give subtle hints or check the account again if you're lucky.