Trying to get a cell phone contract

I have a cell phone contract with Vodacom where I am paying R837 per month. I would like to leave this contract now and move to Telkom where i would be paying R269 per month. I was told by the very unhelpful consultant that I did not meet the required credit checks. She was not able to tell me what the required credit checks were and told me I need to call the ICC or ITC or something. When I asked for the number, she said she didn't know it and I had to Google it. This is UNACCEPTABLE service. Firstly, how can you deny me R269 when I am already paying R837 which will stop when I move over. That would give me even more money every month to save so it makes NO sense how I can be denied.