Cant make payment with money in Apple ID balance

Hi there,

I already added fund into my Apple ID balance. But when it comes to make a purchase for an app, itunes song or even any ‘in app purchase’ they took the money right away from my bank card, not from the Apple ID Balance

anyone know how to fix it? I tried to removed my bank card, and tried purchase again, then the system asked me to update my payment method, while I have about $100 in my Apple ID Balance. Totally not understand now

need help!!!