Refund a Client

Hello, I need to know how to refund a client for a payment she made. I am offering classes thru my website using Squarespace and I was doing a scheduling test of my scheduler and I pay for a class as if I was a client.  

After testing the scheduler I erased my "purchase" but now I can not refund myself and  I have a charge on my credit card. 

How can I process a refund to a client that pays and then cancels the class?

Please help!!

You’ve probably figured this out as your post was a while back, but for anyone else who’s trying to do this — if you go to the calendar view in Sqsp Scheduling and click on the event, then your name (having signed up to test it) it will take you to the payment processor and you can cancel there (not through squarespace). Hope that helps anyone else trying to do the same thing!