Private Caller ID

Vodacom please balance me real quick. So I have a contract with you guys for a couple of months now and recently I can't see who is calling me as everything reflects as private/unknown. I decided call the customer service and I was told that it was not activated as it is an extra charge which I don't understand because my prepaid phone number doesn't do this?? Please explain why I have to charged extra for something that is free for everyone else??? Your service is crazy.