Hi
Follow the instructions here as appropriate, including checking that your address details fully match those on file with your card issuer / bank:
- Pay an unpaid balance in the iTunes Store - Apple Support
- Change or remove your Apple ID payment information - Apple Support
- Payment methods you can use in the iTunes Store, App Store, and iBooks Store - Apple Support
If your payment method is a bank card, then you may also wish to check with your bank, in case it has declined Apple's payment authorisation requests.
If you still need help, then contact iTunes Support:
Contact - Official Apple Support
(I'm afraid that no-one here can look into your billing issue to assist you directly. This is a user-based technical support community - you are not talking to Apple here).