I accidentally purchased an Adobe Stock subscription during an attempt to buy stock images on demand. When I noticed the charges now months later, I immediately tried to cancel but was unable to. I never use this service. This seems implausible and is incredibly frustrating.
I am sorry to hear that you're having troubles cancelling your subscription however I did check your account and it seems that there are some billing errors because of which you might not be getting the cancel option from within your account page.
I'd advise you to Contact Customer Care for cancellation requests and billing queries.
Please see Contact Support FAQ: Unable to reach support through the "Contact US" link if you're still not able to reach the support.