Howdy James,
It sounds like there was an issue updating your Family Sharing payment information from your iOS device. Take a look at the article linked below and verify the payment method was setup correctly, and if that doesn't resolve the issue try contacting iTunes Store Support.
Change your Family Sharing payment information
If you’re using Family Sharing, and you're the family organizer, you need to use a credit or debit card as your payment method. You can’t set your payment information to None. Only the Family Organizer can edit payment information for a family group. If you're not the organizer, you'll see this message: "The payment method for your Family is managed by [Apple ID]."
Get help
If you need help changing your payment information, credit card details, or billing information, contact iTunes Store support. Or you might find the answer to your question below:
- If you change your payment method, make sure your account information matches the credit card information on file with your financial institution.
- If you use an AOL screen name to sign in to the iTunes Store, editing your information on the Account Information page won't update your AOL account. If you need to update your AOL account information, contact AOL.
- If your previous payment wasn't accepted, you might need to change your payment information.
Ciao,
-Jason