iPhone 5s says 32 gig but only has 9 and loosing fast
My iPhone 5S says its capacity is 32 Ggigabytes in settings, but it says I have 9 gig left even though theres no user content on the phone (fresh restore). Also, the amount of free storage keeps reducing in 100mb every once in a while. When the phone was plugged into iTunes, it said (at the bar on the bottom) that there was 9gig free out of 12 total capacity, even though, above the bar, it stated that the iPhone had 28 gig capacity. Please help
iPhone 5s, iOS 8.1.2