Please update to latest iOS then please check the locations below. If that still doesn’t resolve the issue, let me know and there are several other places to check.
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