down grade icloud storage
i am unable to downgrade my icloud storage
If the instructions in Downgrade or cancel your iCloud+ plan - Apple Support don't help, see the following from that support article:
Tap Done. If you can't tap Done, make sure that you're signed in with the same Apple ID that you use for your iCloud+ plan. You can also try following these steps on a different device. If you still need help, contact Apple Support.