Find your user, and select accounts. Find the subscription you wish to refund and select refund from the frop down box on the right. Note that there is a limited amount of time that a refund can be requested.
Refunds are a two step process.
2) Approve / Process.
Accounting | Payment Refunds
You will see a list of refunds awaiting
Change its status to Approved - or not
Hit "Refund Now"
It will process and respond in real time with the result - Approved or Declined - or Error