Tries to buy the same lesson again.
Issue: Sees the full fee (200 yen) instead of 0 yen.
Expected Result: Should see 0 yen, as they have already purchased the course.
Student B/C (2nd/3rd Person):

Tries to register for the same teacher’s

Student A (First Person):

Purchases a lesson from the teacher.
Successfully makes the payment (200 yen).
Student A (Reattempts Purchase):