I thought the teacher account was free, so I subscribed, but I keep getting charged. It’s difficult to cancel! There’s no phone number, no email, and no telephone support.

cancel subscription, https://helpx.adobe.com/account/individual/subscriptions-and-plans/renewals-and-cancellations/cancel-adobe-subscription.html

understanding cancellation 

fees, https://helpx.adobe.com/uk/manage-account/using/creative-cloud-subscription-terms.html#cancel