False promise

I took out a contract with Vodacom using their call centre. I was offered a deal which the amount was inflated compared to the amount promised come billing time. I have made several attempts for the issue to be resolved with no success. Whenever I call its always starting all over from the beginning and all I get is the call centre agents asking me to wait for about 48 hours and others said 7-14 working days while they investigate. I have asked them to give me details of the complaints channel but no one could help.