Anyway . . . In your OP you asked what you should do.
I suggest emailing your player and asking her exactly what happened. Write it up in an email to the grievance committee and have your player confirm to you that it is accurate before you send it. Then send it to the grievance committee, cc to the player.
I suggest telling the truth and being professional. Do not encourage your player to play fast and loose with the facts to make herself look better.
If the grievance is upheld, you both will have learned something.
-- Random Error Generator, Version 4.0
-- Master Moonballer