"in the USA kids can be arrested for nonsense like dont fulfill the school rules" That's wrong first of all, I don't know where you got that from.
And for the refusing reports, I personally believe it shouldn't be a thing when a the report is about a felony. This is something an attorney said, sorry if it's long.
Police departments have a lot of discretion in their decisions as to what crimes to investigate. The law recognizes that resources are finite and priorities must be established, and that not every reported crime merits the resources of a full follow-up investigation.That said, the police department should not (and ordinarily does not) refuse to take a report that, on its face, describes conduct that may constitute a criminal act. It may be that the department is balking because you are attempting to accomplish this report by telephone. You can try to work your way up the chain of command with a demand that a report be taken (remember, that demand is distinct from any demand that the crime be investigated), or you may want to make a thorough written statement, setting forth all of the facts (and only the facts) that you can send to the department by fax and registered mail.
If neither of those efforts is successful, then you will need to contact a local attorney to intercede with the department. I assume that you have a specific reason for feeling that an official report of this incident is necessary, but be sure in pressing for the taking of a report you have a clear understanding that it will not obligate the police to make any investigation or take any enforcement action.