How do I cancel my subscription

God I hate this. I'm well aware this isn't the right place to ask but I can't find anywhere else. I'm supposed to call my school administration for support because it's a school account, but I don't even know who would be expected to deal with this—I didn't purchase Stock in association with any particular department, it was an independent project.

I only ever intended to use the free trial. I had reasons for hedging the grace period as long as I could (I've barely used my trial as it is), but apparently I waited too long, because I can't solve this issue on my own and now I'm out $30 (refund grace period ended today).

When I go to "My Plans," the only thing that shows up is Creative Cloud, which I've likewise purchased independently on a school-linked account. I can find nothing on my account that even indicates that I have access to Stock, but sure enough it's there on my bank statement. I can't even find a way to cancel for next month, let alone this one.

So: If the option is supposed to be there, where is it? If I have to go through a person just to cancel, who might that person be? And if this was supposed to be easy, is there any chance I could still plead my case for a refund, and if so, to whom?

If this question has been asked before, I frankly don't care. Adobe's approach to "support" is driving me up the wall.