Airtime disappearing

On a daily basis, I buy daily bundles. I'm starting to get highly frustrated because sometimes (A LOT) I don't get an sms informing me that the data bundle has depleted, leading me to continue using my AIRTIME (which disappears within minutes.) and i'm not talking about little ten rands. I'm talking about hundreds!! Please pull up your socks because i'm not the only person this is happening to. This calls for a service provider swap! Cell c is not like it used to be. I cant count on you people anymore. Sad, really.