Once data promotion which could not be fully allocated

I got an online approval for a note plus phone. This package included a 20GB once off data upon activation of the phone line. Vodacom only allocated a very small portion of the 20GB once off. I called vodacom so many times to correct this and the all agents were transferring me from one department to another. I am very disappointed with vodacom's service since all agents could not provide a solution to this problem, all they could do was apologize and say they have logged a query which will take 72 hours to resolve. Unfortunately, I feel that vodacom is taking its clients for granted.