Should I take her to see Hannah Montana after this behavior? What would you do?

Ok so here is the dillemma... and I'll try to make a long story short here. My daughter is having some behavior problems at school. Her father and I separated 9 months ago, and she has been acting out ever since. Some of these behavior problems are nothing new, but have gotten worse since the separation. Ok that aside, she was sent to the office for hitting another student yesterday and I got a phone call from the principal. So after much talking with her last night, we had an understanding (or so I thought) about what was expected of her going forward. I reinforced when I dropped her off this morning and threatened NO Hannah Montana if I get another phone call today. (concert is tonight) So.. I GOT ANOTHER CALL. She picked a fight with another student and now will be suspended on Monday! I am in shock and obviously we have bigger issues to deal with here, but as for the concert, do I really not take her now? I feel I shouldn't, but these tickets were insanely hard to get, and very $