I keep getting emails telling me that I have used 14.5GB of my 15GB but all of my devices say that I have only used 7.2GB. Any ideas how to fix this?

Question

For the past week I have been getting emails as per below:
You are currently using 14.5 GB of your total 15 GB of iCloud storage, which means that your iCloud storage is almost full. When your storage is full, device backups to iCloud will stop and apps will no longer be able to save documents to iCloud.
To ensure that your iCloud services continue without interruption, you can free up space or buy more storage by following the steps below:
To free up storage in your account:
Step 1:
On your iOS device, go to Settings and tap iCloud.
Step 2:
Tap Storage & Backup.
Step 3:
Tap Manage Storage and choose items that you’d like to delete or stop backing up.
For more information on managing your iCloud storage, please read this article.
To buy more storage:
Step 1:
On your iOS device, go to Settings and tap iCloud.
Step 2:
Tap Storage & Backup.
Step 3:
Choose Buy More Storage.
You can also buy more iCloud storage from a Mac or PC.
My Mac, my iPhone and iPad are all telling me that I am only using 7.2GB of my 15GB storage limit.  Any ideas what could be causing this?
Thanks
Pete

Answer 1

I received this email today and have no idea why.
Dear Daniel Freeman,
You have now exceeded your iCloud storage, including an additional amount provided to allow you to continue receiving email. As a result, you will not be able to send or receive new email messages with your iCloud email address until you free up storage space or buy more.
To free up storage in your account:
Step 1:
On your iOS device, go to Settings and tap iCloud.
Step 2:
Tap Storage & Backup.
Step 3:
Tap Manage Storage and choose items you’d like to delete or stop backing up.
For more information on managing your iCloud storage, please read this article.
To buy more storage:
Step 1:
On your iOS device, go to Settings and tap iCloud.
Step 2:
Tap Storage & Backup.
Step 3:
Choose Buy More Storage.
You can also buy more iCloud storage from a Mac or PC.
I have not changed anything with any of my iOS devices (iPhone 4s, iPad2) or my Macbook Pro. I have 3.21GB out of 5GB of storage space free so I dont understand why this has happened.
will my iCloud email service still work?