iCloud storage not available after purchase

Bought some more iCloud storage two days ago (5GB to 20GB) but its not available in my photo stream yet.

I followed the 'you've ran out of storage' link and purchased 20GB. And my current plan in the storage settings is 20GB, with 14.8GB available.

However, in my photo stream, it says I've ran out and I keep on periodically getting pop-ups saying to buy more storage.

Tried rebooting - no joy.