Greetings, Dhimbs.
I see you're trying to update the payment method you use for iTunes & App Store since it's being requested to purchase/update/download apps. When you add your payment method, you're met with a message that it's been declined. I'm happy to help.
If your payment method is declined, or you have a billing issue with a previous purchase in the iTunes Store -- If there was more to the message than just "declined" review this support article.
Payment methods that you can use in the iTunes Store, App Store, and iBooks Store -- Make sure the payment method you're choosing to use is supported.
iTunes -- Official Apple Support -- If you're still having problems updating your payment information, contact iTunes Support for help. Click the link and choose your country or region, then follow the prompts to contact iTunes Support.
Take care!
Thank you for trying those steps, Dhimbs. Since the issue still isn't resolved, please contact iTunes Support.
iTunes -- Official Apple Support -- Click the link and choose your country or region, then follow the prompts to contact iTunes Support.
Have a good day.
Thank you for your help. I have tried everything but it's not helping.
Failing to update billing information
