I need to cancel my plan

I subscribed to Firefly as part of an Adobe marketing course on Coursera. I entered my card details to activate the 3-month trial period, as explained in the course. However, I got billed for the subscription even though it was stated as free. I’m trying to cancel the plan from my account (Manage plan> Cancel your plan), but it sends me to a page that doesn't load (screenshot attached). I tried from my PC and my phone, same dead end. I’m trying to contact support, but every link sends me to a guide steps and FAQs.