iCloud storage

Doh, I was not thinking - sorry! In iOS you need to go to your AppleID in settings, tap iCloud, then "Manage Storage" and there should be a "Change Storage plan option" there, tap it and you should see your current plan and the optional upgrades or downgrades.

If that is there, and on the previous settings tab it says "200 GB" then yes, you have an iCloud subscription plan. The 5GB warning would be therefore an error, but if it persists Apple icloud support may be able to figure out why its popping up for you.

I have no idea then. If you're subscribing to an iCloud storage plan, it should be in your subscriptions. What does your iCloud available and total storage show as in settings?

Sure - I posted the link to Apple iCloud support previously so you can use that to get in touch with them.

These are user community forums, as explained when you created your account here.

First, check your subscriptions with https://support.apple.com/en-us/HT202039. As long as the subscription looks right, then check your storage by https://support.apple.com/en-us/HT204247

If those check out, but you keep getting the notification, contact Apple support - https://support.apple.com/icloud