The method used to cancel a Univer.se Pro subscription will differ based on the platform you are billed through.
Apple Subscriptions (purchased in the iOS app)
Like many other apps, your subscription and billing are handled by Apple to keep your information safe. We do not have the ability to alter your subscription if purchased through Apple.
If you need to cancel your subscription so that you don't get charged again, you can see how to do so here.
Please ensure you are logged in with the same Apple ID as you used to create your Univer.se site when viewing your subscription information.
If you also need a refund, you can read more about that process here.
Web Subscriptions (purchased on web.onuniver.se)
Univer.se now offers the ability to subscribe to pro directly. Currently, it is not possible to manage your subscription if purchased form web.univer.se.