Unfortunately, vouchers can't be applied once an order is complete. Vouchers need to be redeemed during the checkout process.
To use a voucher, simply enter the code in the "Overview" section of your order and click "Redeem." You'll see the discount reflected in your order total before completing your purchase.
If your order hasn’t been processed yet, you can cancel it and place a new order using the voucher. For more details, check our information on canceling or changing an order.