You can complain to the Education Bureau. The lawsuit can no longer be withdrawn, and the tuition fee can be refunded, but only if the students have to go through the formalities of dropping out of school. The specific calculation is the annual tuition MINUS the time spent studying, and the tuition is calculated on a monthly basis.
Tuition fees are charged by academic year or semester, and may not be collected in advance across academic years. If students drop out of school or finish their studies ahead of schedule after paying tuition fees, colleges and universities should refund the remaining tuition fees on a monthly basis according to the actual study time of students.