Hi, @falissa! That's a great question. The answer will depend on how you placed your original order.
Did you checkout as a Guest? If so, you'll need to locate the cancellation email you received for the order. In that email, you'll find a voucher code for the 120%. Next, you'll need to log in or create a Registered account. Then add the voucher code under StubHub Wallet. Once you do that, you'll see the credit under Discounts/Gift Codes during check out for a new order and just need to select it to apply.
Purchased under a Registered account? The credit should already be under your StubHub Wallet! You can fast forward to just selecting it during checkout to apply to a new order.
Hopefully that helps! If you're not able to locate the email with the voucher code or are still having trouble, please send us a Private Message with the email address and zip/postal code on your account!