How do I cancel my order?
To cancel your order, visit My Orders, or search for your order here. If it can be cancelled, you’ll see a button with the option to cancel each item.
https://www.samsung.com/nz/shop-faq/returns-and-cancellations/how-can-i-cancel-my-order-on-the-samsung-online-store/
If your order cannot be cancelled, opting for a RETURN will be the fastest way to get a refund.