To Redeem a voucher, go to the orders tab on the left of your dashboard.
You will now see the most recent orders. To find a specific voucher, enter the voucher/order number into the search bar (other fields are available through the ‘filters’ dropdown).
Once the voucher/order number appears in the list, you can then click on it to expand the order.
Once the order has been expanded, you can click the tick box to the left of the voucher number to select that voucher, then click the action tab at the bottom of the page and change it to ‘Change status’.
A new drop-down menu will appear with a number of different statuses you can change, selecting the ‘cancel’ from the drop-down and clicking ‘update’ will cancel the voucher.