Artchill,
Interesting sevara, although it sounds a bit far fetched to me to say that the school is implicitly taking responsibility. Even if it were true, I could hear it for textbooks, which belong in a locker, but not for money.
Supreme, you can ask for the name of the Rabbi you are speaking to (“May I please ask with whom I am speaking”). Also, keep in mind that the answer you receive is relevant to you alone, since the other parties are not there.
Daniela, the first step is her monetary obligation. If she is not obligated, she must consider whether it’s worth upsetting her friends, or pay anyhow. You are 100% right, though, that she needs someone to speak to, especially based on the other thread.