Cell c black is ****

Disappointed with cellc. I really regret getting this cellc black data. It has been using my normal data bundles instead of my cellc data and it is depleted every month for the past 2 month. While my black data hardly ever reduces. Cellc gives you the run around when you call and tell you to call the black department who will also tell you to call the normal cellc call centre as they do the billing. I have no idea what to do as I'm paying for something that I can't use. I might as well have just used Netflix or showman as they have updated shows anyway.