False info provided to me by Vodacom to accept a new contract

Vodacom contacted me round about 6 or 7 November to tell me about this wonderful promotion that I as a specific Valued customer qualified for.She mentioned to me specifically that I will be receiving 20 GB data monthly and that it will accumulate and never expire.I confirmed with her that it will not expire and accumulate and she confirmed once again.On these conditions I accepted the new contract of R199 pet month.I would like Vodacom to listen to the recorded conversation ad this is false information provided to get a customer to take out a contract.I discovered to my dismay that if you do not use your data monthly it expires.I want to know from Vodacom what are they going to do about this false information that was given to me.I want the contract as explained to me.