Cell C 900 Cell C to Cell C Minutes for R199

Fed up with Cell C, I bought 900 Minutes for R199 any network, they gave me 900 minutes for R199 cell c to cell c, they even sent me an sms that I bought any Network minutes, but I can only make calls to cell c only, when I called the Customer service the consultant tell me she can't help me with this, and when I ask her who can help me she said no one can help, I m leaving Cell c for good this time I don't have problems with my other Network Numbers, at first they take my minutes with out being notified now this. How can I buy cell c to cell c 900 minutes for R199???