First a disclaimer: I think this is outrageous and hope that her account is restored.

Now my questions:

Does her account use her home address? That seems unlikely as she is in Norway but is dealing with Amazon US. What are the rules for purchasing content when you're not resident? Could this be the problem? If so that sucks.

Secondly, it appears that she began her Kindle odyssey with a used Kindle. Could that be what links her account to a fraudulent one? A unique ID from one of her devices has been used by someone else in the past?