The 'Data Usage' screen is scaled to 100GB . My data plan is limited after the first month to 500MB because I am somewhat Scots. How do I rescale that graph? My Samsung Meta has Android 4.2.2
Click on the handle (a solid dot) on the right side of the red horizontal line above the orange line, and drag it down to 500MB. That adjusts the scale of the graph.
Look for the lime green arrow at right to see the handle.