Very defiant 5 year old in school.. help?

Our daughter is 5 and she is very defiant in school. We are completley out of ideas. At first my husbad and I thought there might be a problem at school, so we did not punish. We talked with her and met with teacher, even went as far as to go and observe the cl one day. After that we realized it was a behaivor problem. So we started getting a report and everyday it was bad she got punished. We tried no going outside, no tv, and taking away every privelage we could think of. We did not get the desired result, so we have gone to . Everyday she gets a bad report she gets a from either her dad or me when she gets home. It has cut down on the bad behaivor a lot, but she has gotten several ings as well. Its just not how I. Envisioned us parenting. Its still about once a week she gets a for misbehaving on school. She is not getting beat, but we have began to a little harder to make them more undesireable. Is this wrong are we terrible parents.. please help?