OK, check these three locations please;
Each card also has an address associated with the account. Please follow this path;
iPhone > Settings > Apple ID (Your Name at top of screen) > Payment & Shipping > tap card to edit > tap Billing address > tap edit (upper right corner of screen) edit necessary changes
iPhone > Settings > Apple ID (Your Name at top of screen) > Payment & Shipping > Shipping Address (edit or delete address
iPhone > Settings > Wallet & Apple Pay > Transaction Defaults (scroll down) > Shipping Address > Edit (upper right corner of screen) > either Enter New Shipping Address, add new address or edit/delete addresses
When you’re done, there is one more place that may be the issue.