Frustrating week

I am reliving all the times when Evi's 4th grade teacher said "5th grade will be hard". We had a situation that has caused quite a stir in our home. After attending the same school for 7 years, never having detention before, this is what happened.
Evi has a teacher who is new to teaching. At the beginning of the school year, the teachers said that if a child gets a D or F, that the parent must sign and return the test. Also, it was mentioned that for 'Discipline" there would be 1) a verbal warning, 2) e-mail or note sent home, 3) phone call home, 4) meeting with the principal, 5) detention, 6) suspension.
Evi took a science test last week (that apparently she forgot to mention) so she flunked it, along with 16 of her fellow 24 classmates. I never saw the test, needed to sign it, or any of the above mentioned methods of "discipline". So last Friday when Evi gets in the car, she informs me that she has detention, and what she is most upset about, is now she no longer be a part of Select Choir or Safety Patrol. When I asked what had happened, she said she flunked a test, and that for the past 3 days she had been going into class during recess, to correct the answers. When she asked for help, the teacher was not helpful, and that the teacher said they needed to come in for recess to do the work (Evi didn't know she could bring it home, since she kept saying to come in for recess to do it). So when I got home on Friday, I called the school to talk to the teacher, to see what was going on. She had left for the day, so I asked the secretary who I could talk to about this. She passed me to the principal.
The principal said to come in Monday morning to meet with her and the teacher. When I got there, Evi's teacher could not find one positive thing to say about her. She said that it is not her responsibility to let me know of Evi's grades, and that if Evi paid more attention in class she just might "get it". I asked " what about the parent signature that is suppose to be on there, the teacher said that since that didn't work last time, that she didn't think it would work this time. After 1 1/2 hours of talking, the principal called Evi in, asked her to tell her about what happened. Evi explained it, then said the teacher made all the kids that flunked the test stand up in front of the rest of the class while she called parents. That is a low blow in my opinion.
That night the principal called me back, and said that the kids would not lose select choir or safety patrol from this, and that she felt that she needed to back the teacher, but could also see my point, she said that I could have Evi do the detention or not, it was up to me, and that she told the teacher that she needed to clear detentions with her before doing it. I told her how I felt that the teacher was very defensive during our meeting and she agreed. I told her it may be a good idea to give her some pointers before she has another parent meeting.
So Evi has served her detention, and now I am frustrated at the lack of communication that is going on. I still haven't seen the test she took Friday, or know that score. What is a mom to do?? Any advice?