2 battle net accounts banned, any ideas?

Just had both my battle net account banned within 10mins of each other.

This is the email I got:

Action(s) Taken: Account Closure

The Battle.net account has violated the Blizzard End User License Agreement. As a result, this Battle.net Account and all associated game accounts have been permanently closed. As the owner of this account, you are responsible for all actions associated with it. We will only overturn penalties if there is evidence of a compromised account. Read our Account Hacked article for details: https://battle.net/support/article/9852

Blizzard Entertainment reserves the right to terminate access for conduct of this nature, with or without warning, as noted in the Blizzard End User License Agreement: https://www.blizzard.com/company/legal/eula.html.

Regards,

Blizzard Entertainment

One is used by me, one more by my s/o in the same household.

Nothing I can think of that would trigger this except I bought prepaid 60day WoW gametime cards from G2A for both accounts. Is there any way those codes could have caused the ban?

Not really worried as we were only level 20ish on SoD and I can appeal the charges from G2A on paypal, but im worried about creating a new account and having the same thing happen again.