In any case, you did not answer why they are not using the ingame reporting when it is completely anonymous so they dont need to worry about that... Perhaps there is a miscommunication somewhere in this and everyone is trying to act a bit hastily. (I understand that she might be afraid to act and you are trying to be the knight in shining armor, but you must help in a way you CAN, which is to explain to her how to report the person...) If ingame reporting is not working then she can open a support ticket which is also anonymous...

Also, i hope this girl has since blocked this person (added to their blacklist).