There are a number of ways to find out how much you have refunded to an event. One of the easiest report categories uses the ticket transaction category because it allows you to show details and totals to certain kinds of transactions that happened between a date range.
Some key ones are:
Transaction History By Event - as explained by the youtube video in this page (click to see in youtube) This one is quite relevant since it shows all the refund transactions with the detail who you refunded to
If you are only interested in totals for some events, some of the other transaction based reports might be better suited. Be sure to provide appropriate criteria for the report such as:
The date range after after which you want to consider transactions - eg all transactions after a certain date
If you have refunded some of the tickets to a donation or a gift certificate and want to find out the amount returned to the patron, then:
Find the total refunds as per the transaction reports
Find the total exchanged to a specific donation campaign (for ticket returns in that same date range). You could also use a transaction report for that, but specify new donations to the campaign of choice.
Find the total exchanged to a specific gift certificate type (for ticket returns in that same date range). You could also use a transaction report for that, but specify new passes/gift certificates you used.
The total cash returned to patrons is:
Total tickets returned - total donations purchased (for ticket return) - total gift certificates purchased (for ticket return>