You are required to ship to the address that was provided when the buyer paid.
If you change the shipping address, you will void your seller protection.
Verify that the address change request came from the same account ID as the actual buyer.
Then consider cancelling the order, resulting in a refund to the buyer.
Then relist the item for the buyer to purchase, providing the correct ship to address during checkout.
I do not know how to use a different address when I created the label and with different size of the package.
If the package dimensions / weight are incorrect on the label, you may need to void that label.
Orders / Shipping Labels / Actions (for this label) / select VOID.
