I'm not an american apologist by any means, and it is a dark pattern, but it is very clear at point of payment what you're paying, and what period it's for. The drop-down unexpanded clearly says "Annual Plan, paid monthly".

Yes it's a bait and switch, and adobe deserve to be called out on the bait and switch but thats not what this thread is about, it's about someone signing up to (clear at time of purchase) annual billing and wanting to cancel early.