Worst service ever

Okay so someone at Cell C tried to contact me and left a voicemail which I am unable to hear, the person emailed me and I rep**** two times that he can phone me now or else give me his number which he never responded to. What more must I do to clear my name from the credit bereau. All I want is to pay CELL C their R135 and for them to clear my name, I don't understand how that can be so difficult, All they can do is email me the banking details so that I can pay the LARGE amount I owe and for them to clear my name