Q: account issue

Just follow the instruction as given.

Hi

Check that your payment details are correct, including that your address details match those on file with your card issuer:

• 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 the issue then persists, contact Apple Support for assistance:

• Contact - Official Apple Support
• http://www.apple.com/support/itunes/ww/

Or by submitting the form here:

• https://www.apple.com/emea/support/itunes/contact.html

(I'm afraid that no-one here can investigate your billing issue - this is a user-based community, not Apple Support).