Data usage really high on iPhone 4S? - 1

My iPhone 4S says there's 12.7 GB used and only 899 MB available. But, as seen in the pic below, there's definitely not 12.7 GB used. Help?

Data usage really high on iPhone 4S - 1

Added (1). I don't think so. I'm trying to record videos but there isn't enough data.

I've never owned an iPhone only androids but could you perhaps be getting On-board device storage confused with data usage?

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