Missing storage in iCloud
My iCloud is warning me that the storage (5GB) is getting full and only 143MB is available
After I went to setting -> iCLoud ->Storage -> Manage Storage, it tells me that
Backups of iPhone & iPad is 1.7GB
Documents & Data is 461.3MB
but at the bottom, it said
143MB available of 5.0 GB on iCloud
where is my 2.9GB?
I guess that it may be occupied by my backups of my old iPhone/iPad i use previously. But I don't see these backup in the Backup List.
How can I get back my 2.9GB storage?
iCloud-OTHER, iOS 9.0.2