How to get a refund for movie rental

I rented a movie via appleTV and after commiting to the rental found I needed to wait 3 hrs for the download to complete before I could watch. I came back 2 days later and discovered that no progress had been made. I changed to lower resolution on settings but could not change the download time on the movie that I already started. I was willing to let the movie download and comeback later, but do not find any help to accomplish this. At this point, I will accept a refund and go back to netflixs, but there is no apparent way to request this. Love apple products...until you need help!