I did it for a different program and ran into a small problem. When I went to log in to get cancellation info, every link would bring me back to their main page. I couldn't get an email, phone number. . nothing. I finally got to a page with a general form to send to different departments, so I sent a note to Customer Service (or something like that) that their site was faulty and I couldn't get contact information to do it myself, please cancel my account. A couple days later I had an email that as a "courtesy" they cancelled although the only way to cancel is to call.
So they DID cancel before charging me. . . just had to jump through a couple hoops.