Problem cancelling Peacock Premium

I've paid for a subscription to Peacock Premium for several years before it became free for customers with a Gigabit package on June 26 (yesterday)  I tried to cancel my Peacock Premium subscription on PeacockTV.com, but got a message saying that I would have to cancel it on XFINITY, because it was billed by XFINITY.  When I logged into my XFINITY account, I confirmed that I have a Peacock Premium account that is "Billed by XFINITY-US," but I am unable to cancel it on XFINITY, and the message is that I have to go to peacocktv.com to cancel it.

It's an infinite loop.  How can I break out of it and cancel a service that I now receive for free?