I recently had to cancel a trip where the airfare was paid for with SW points and the early bird check in, as well as the post 9/11 service fee, was paid for on a credit card. When we cancelled it, we got the service fee refunded back to the credit card and lost the money paid for the early bird check in. We did not get a SW credit or a refund to our card. Maybe this varies if you don't book the flights with points?