Schools configure their refund policies. The College Board charges the school a $40 cancellation fee for each AP exam canceled after their November order deadline and schools usually pass that on to the student. Schools may charge more than this amount to cover the cost of processing payments and refunds. Please contact your school or the College Board for more information.
According to https://pages.collegeboard.org/contact-us, you can reach the College Board at 888-225-5427 or firstname.lastname@example.org