***** NOT A TEACHER *****
Maybe something like:
You said that you were coming, but now you're canceling. That's really not a right thing for you to do! / You're
really wrong to do that! / It's just not right for you to do that! / What you're doing is really not right! / What
you're doing is really wrong! / You're really being unfair to do that!
Student or Learner