Taking action

Hello! I have a question. My school isn't the best, I have missed one week of school and i am planing to miss another one. I am very close to my first A-level and I haven't learned or practiced enough to get the grade i want. So as in school i have a lot of frees, and in my classes one teacher hasn't come since two weeks ago, in another one the teacher comes sometimes and when she comes she gives us an exercise paper to complete wich takes us only 10 minutes and then she leaves for the remaining two classes, dissapearing. In another class the teacher is very bad, she gets crazy because of some students and she doesn't know how to control it and just ends up shouting or giving up and not doing anything. In another of my clases the desks have been set up so that some students are facing backwards to the teacher, so i cannot pay attention correctly. After protesting all year they changed me from place, but the course has already finished and it's useless.

I thing that despite this school being private, and my parents paying 9000 euros for the school yearly + the AL exam costs. I couldn't suport it, for the past four months ive been trying to study in the free place where it's suposed to be to study but with all the other students, its impossible ive studied outside in winter and everywhere where you can imagine. Being so tyred of this i've decided to take it into my own hands, my parents understand everything and i just want to make the most of this little time i have left to get more study done. The school doesnt have any policy and in my reasearch i also didn't found any attendance policy of Globeducate wich is the organization that owns my school. I think this school is not a comunity but they just want all the money possible. The teachers are horrendous, they shout at you for having a jacket on or if your shoes are black instead of blue.

Would the school make me repeat grade or do something for my absense in school (Teachers aren't teaching anything, we are doing "revision") so i wouldnt be missing any school material. What is the worse that can happen?