iCloud problem: "iCloud storage is full" message
Apple now has a web interface to view and manage (some of) your storage.
- https://www.icloud.com/#settings
I would go there and verify that the web interface matches the iOS device. If so, then you can go to the photo library and purge the Recently Deleted or work through the options given here:
- https://help.apple.com/icloud/#/mm93f1a9aac0
From your screen shot, you might need to download documents from iCloud Drive, but worst case, you will have followed the latest cleanup steps if you need to reach out to iCloud support to have them look at the code that checks free space and validate it against the lower numbers you are being shown on your Mac.
Apple also provides free support for accounts like AppleID and iCloud so you can get personalized help from:
- https://support.apple.com/