Product mis-selling

I was mislead to take up a contract that comes with a we grow educational voucher in August 2021 and to date I still have not received the voucher. when I make follow ups with Vodacom I am being told that I should call the company dispatching those vouchers and when I call the company they told me that they do not deal with the we grow vouchers. when i try to cancel the contract i'm being told of the 14 days cancellation period or else i need to pay the full contract amount at once. I am not happy with this because why do i have to pay if they did not keep their end of the deal. I have lost all faith in Vodacom because this is *****.