No notification of data being low

<p>I just lost over R200 worth of airtime, i bever got the sms to say that i have less than 15megabytes of data so i figured i still have enough. Until i checked to see how much airtime i had, only to discover i have been using out of data bundles. </p> <p> </p> <p>This is really not good, considering the charges and the amount lost. Im so over Cell C at times i wonder why im still on this network.</p>