After a few denials on the web form (even after mentioning
https://www.transportation.gov/brief...carrier-refund ), I called in to get my award flight refunded. The person on the phone seemed to know that I had already attempted a refund via the webform, but confirmed that I was aware of the change option, asked me why I didn't want the change option (to which I explained that I do not expect to book a future high-mileage ticket as high as the one I had booked), and then after placing me on hold for a few minutes, said the refund would be processed.
I was surprised the webform attempts were easily accessible, but the phone call was pretty straightforward and there was not much trouble getting the refund.