I am sorry to hear that, Moriq, but I can assure you that nothing with this is automated. Looking at your sister’s account there was absolutely suspicious activity which caused this action.
Based on what I am seeing it was likely compromised and in those cases an account may be closed because of the actions taken by the compromiser. It also allows us to stop any further damage that might be caused by this person until your sister can regain control of the account (I highly recommend adding an Authenticator once they do).
There is information in the Support Article here.
There is a link to put in a ticket. They may also want to try the following option. They do not need to log in to submit a ticket.