It took me something like two years of attempts to actually cancel Amazon Prime from their dark patterns. They also include brow beating you on possible money "lost" if you cancel because many of their pages have a dark pattern of suggesting they offer no refunds or prorating, especially if you are cancelling the same day of an automatic payment.

(It turns out that do actually refund it, otherwise in my second attempt I would have considered taking it to a lawyer and/or the BBB. It's still disgusting that they make you click through a bunch of "are you sure, you probably won't get a refund?" text before that.)