It's a tough situation because you weren't there and don't really know. I personally try to not take sides in situations where I don't know what happened. So, the first thing I'd do is try to figure out more about what happened. If you can't get to the bottom of it, stay out of it - sort of. One way to handle it is to reward or punish your daughter for some sort of behavior report she gets from school, like whether she was "on green" or got a "smiley face." That way, you aren't punishing her directly for something she did, but for the behavior level she was on. You can then stay out of the situation and tell your daughter, "I wasn't there, so it's not that I'm not believing you - I just want you to do well at school, and if you come home with a good report you get a reward, and you come home with a bad report, you have this consequence." The only problem with this would be if she keeps getting bad reports from school. In that case, you'd probably want to meet with the teacher and come up with a new plan, because the old system wasn't working.

In this situation, I wouldn't punish her for what she did. I'd punish her for getting a bad report at school.

One other thing to consider - try smaller consequences. If you jump right to the big consequence (like taking all of her game systems), she'll get used to it, and you won't have anything else to do with other situation. So, make consequences shorter (for example, taking her game system for 1 hour instead of 4 weeks), or less (for example, taking one game away, not the whole system). That way you have more things to take away if you need them later.