In short, a refund for an online payment that has been processed will return in a payout that reduces the overall amount of the payout.
To check whether a refund has come through in a payout, navigate to the Master Payout Listing query on the Payments Processing Homepage. in the query design, find the Refund Value field and set to the criteria to "is not equal to 0". Run the query.
In the query results, locate the specific gateway for the payout and review the refund amount column. You can drill into the payouts listed to view the specific refunds that have arrived in those payouts.