Once again Cel C Unfair to customers

Very disappointing. They advertise or urge you to switch to triple bonus plan to get triple your money. Which I did and wanted to buy a 3 gig data plan for my months need. So I bought R300 worth of data and yes immediately I have a bonus of R600. Wow, only problem is, you have to use it within 24 hours. How unfair. Now within a day I must all of a sudden use R66 worth of airtime or lose. This is not fair. Now recently I have bought R50 to get only R100 which it was suppose to be R150 and then R100 and got R200 where again it was suppose to be R300. How is it possible that they can be so dishonst and unfair to their customers, is it because there is no real competition