Check the three locations below,
Each card also has an address associated with the account. Please follow this path;
iPhone > Settings > Apple Account (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 Account (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
In addition, if your using Safari browser it could be the cached data used for Autofill.
Lastly, the Me Ccontact card in the Apple Contacts app must have the correct address in the first address slot.