CLI not working

For the last two weeks i have been trying to sort out the CLI on my number. but have had no success. I keep calling the call center and they cant sort it out. This is causing an incredible amount of problems since i dont know who is calling if i miss the call, i cant call back. Vodacoms service is unacceptable. If i could help it, i would cancel my contract right now but i have just got the contract and i am stuck. unfortunately.