Well, not only in their iPhones. And not in the same cloud storage provided by the phone. The only backups you really control are the ones in your possession, so you must keep offline local backups of anything really important to you.

The big marketing point of cloud storage was that you would not need to worry about owning and maintaining local storage, but they conveniently downplayed the fact that they could lock you out of your own files at their whim.