40%할인 플랜으로 변경했는데, 할인가가 아닌 원가로 결제되었습니다. 구독취소하고 환불해주세요.

The discounted plan may have been only for new subscribers.

no one here (or elsewhere) can cancel for you.  you have to do it yourself:

make sure you're aware of the cancellation terms by selecting your plan type (at the top of the page here), https://helpx.adobe.com/manage-account/using/creative-cloud-subscription-terms.html



and for info on how to cancel your subscription, this page describes the few steps involved, https://helpx.adobe.com/manage-account/using/cancel-subscription.html

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative.



if you're unable to follow the steps described, you'll need to await help from an adobe employee for the next step.  (if you don't get a reply here from a badged employee within 24 hours, repost.)