Canceling a subscription
I am not given the option to cancel a subscription regardless of the device (phone or Mac). Any ideas?
Has the subscription been canceled automatically or in the past?
In that case you will not see the option to cancel it in the list of your subscriptions:
If you want to cancel a subscription from Apple - Apple Support
If that is not the case, contact the official Apple Support about that, using the "Report a problem" option:
https://reportaproblem.apple.com
You can also click on the link on your receipt that you received for your subscription, to get to that page.