Missing Data bundles

<p>I bought data bundles worth 500 mb and was given 250 mb for free on the 15 February 2017 between 9:00 10:30. I didn't log on to Facebook for the past 7 days or logged on to instagram for more than 3 minutes but used Twitter for less than 5 minutes today. When I checked my balance I had 420mb left, after checking my balance around 16h20 my data was gone not even a message warning me about my mbs depleting.</p> <p>I called 173 and a Mtn champion put me on hold for a very long time. All I'm asking for is where did my data go?</p>