TOPIC: Issuing event refund creates a new registration???

Hi, I created new registration from the fronend, then issued a PayPal refund and credited back the registrant full amount, but DTRegister created a new registration record with the same name and negative event cost amount, and reduced the number of available seats at the event (instead of increasing it due to the registration cancelation). How can this be resolved? I am sure we will have many event cancelation, what is the correct path to cancel a registration?
Thanks