Should i stop being friends with this girl read the story bellow?

One day me and my 3 of my friends were at cl and they took my binder, which contains all of my school work. I was lookin for half of the cl period all around the room. I even swore them to secrecy and they still wouldnt admit that they had it. While this was all going on the vice pricipal was standing behind our table watching this all happen. my 3 bffs starting laughing so I new that they had it. So I said give it back and they didnt give it back for another 3 min. So then they finally gave it back and the vice pricipal started yelling at them and told our whole table that we had to come back for detention. So later came back for detention. The dean and guidance counselor came in. I didnt saying that much besides the fact that i was freaking out during cl. anyway now my friends are mad and me bec i didnt defend them at deten. . bec they stole my binder. they have been mean and told me to go away and sit at another table at art even though supposedly they were my best friends