ok, I am not sure if there is actually some other way but here is what I did. Little roller coaster so be ready 🙂
I went on hulu's site on my computer and pretended to sign up (not throgh facebook! - click the small link at the buttom) . As I filled out my email address and other info it showed me that the email address exists in their record. (it is the same email address I use for my apple account).
Then I clicked "forgot password" link and they email me a link to reset my password. I reset my password (well, I actually created one since I never signed up through their site). Once I was in hulu's site, under my account info there was a link to cancel free subscription. Once you go ahead to cancel it, they will show you a small and funny clip gathered from different shows all saying "Don't go". Once it stops playing there will be a link at the bottom that says "Cancel" and "Don't cancel". Just so you know, non of these links are easily and readily visible so look carefully.
As I said, I don't know if there is another way but I just used my senses and went along with steps and I found my way out. Good luck