Principal lied to my friend on her cell phone!! what should i do??

At out school we have two "teams" you can be on, the teams are completely separate and the kids on separate teams dont interact, or see eachother, my friend was put on West and called the principal to switch because she was in the same homeroom as her twin brother (they fight dramatically, they cant live together) and she called the principal who promised her to be switched to East, that was a month ago. They never called her, so she called today and the principal said "Sorry, you're on West now" Even though she PROMISED East. My friend is crying and can't do anything, they cannot do this, ESPECIALLY not calling her even to tell her! What can I do? Call the Superintendant???