When you cancel and refund an order, you have the option to send the refund to your customer as a voucher that they can spend on replacement tickets.
To see a list of orders made using 'refund to voucher' codes:
Export your order report (either your Order report or Line item report)
Filter to show orders where:
The payment method is 'NO COST'
There is nothing in the 'Discount code' or 'Voucher code' column
There is a monetary amount in the 'Order value' column
❌ It is not currently possible to see a report of all issued but unspent vouchers sent as a refund.