Once your voucher expires you can apply for 80% credit in the form of points.
To apply for your credit, log into your account, click My Vouchers and then the Expired tab.
You will see a button beside your voucher that will allow you to apply for the credit. Click the button to claim your credit.
Please note, you have 6 months after your voucher has expired to submit your refund request.
Once you have applied for your refund, the points will be applied to your account within 48 hours.