Unfair sale contract - Consumer Complaint for Vodacom - Head Office

An agent called me saying because I am a loyal customer of vodacom they are going to give me a free gift and I will only be paying for the data an amount of R 129.00 only to find out th eye are going toe debit and axtra R 399 Is that they think that Im crazy to have a new contract on top of the other one I understand my financial status I cannot afford to have any new debt