They do intentionally make it difficult to cancel, but you need to stick to your guns and say, "I'm not interested, please cancel it." They will persist, but keep saying, "I'm not interested, please cancel it." After about 10 minutes on the phone, they will realize they are wasting their time and will process your request.
I did it last week. Good luck!
pattycake's FICOs: 6/2/10 - TU: 708; EX: ???; EQ: 749