Microsoft do not un-ban previously banned consoles as they are permanent. They do not ban people's consoles/accounts lightly, they do so after several investigations.
The most common reason for a banned console is modifying it, but there are other reasons such as marketplace theft.
You might want to post in section 14 in order to get an official answer. Although they might just delete your thread and post a link like below as they do not discuss console bans.
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