Need to cancel my storage subscription

Cancel upgraded iCloud storage by downgrading to the free 5GB plan. See instructions in the following Apple article: Downgrade or cancel your iCloud+ plan - Apple Support

If you don't have an Apple device or a Windows PC to use one of the methods described, click on the following from that support article:

If you still need help, contact Apple Support.

iCloud is not tied to a single device.

Just because your iPad does not work, does not mean you cannot still use your iCloud storage on other devices signed in to your Apple ID.

To cancel iCloud you will need a Mac, iOS Device or Windows PC with iCloud for Windows logged in to your Apple ID, at which point they can access the iCloud subscription, and take advantage of the storage through there.