What's the name of this movie?

so i saw this movie when i was maybe...9 or 10, and i just remmeber a few scenes from it, but the curiousity is killing me. lol. so anyways, it's about a girl who starts an affair with her teacher or something, and there's this scene where they're in the car, and she's about to take her clothes off for him. and later, her mom finds out, so the teacher gets send somewhere or something, and the girl keeps trying to call him, and it never got through. something like that...thanks