Teachers cannot answer student's email when the student is not in school?

People are skipping school because A Levels have already started and school is not giving us exam leave. A student emailed a teacher asking about something related to A Level content and the head of 6 form told the teacher that she's not allowed to reply to the student because the student is not in school. Is this normal?
I skipped school today as my first exams are in a few days so I just heard this from another student. I trust her though. My school does seem to be a bit... abnormal.
Also, do you guys have exam leave? Mine doesn't start till after half term but all my other friends from other schools have already had their last days last week.