Default [Q] Data usage calculator disappeared in settings

As the title, my friend's ZR's Data Usage calculator below bluetooth settings disappeared last night...
The phone is locked and never flashed a custom rom, purely stock.
As I don't have a ZR and never met this problem on my Xperia V, I suppose someone should maybe have this problem here in the ZR forums.
Anything I could do to get it back?
My Devices:
Xperia V
HTC Desire S
Xperia Mini Pro