MISLEADING VODACOM PROMOTIONS

Last year november Vodacom was running a special of 50% on data, little did I know I was taken for a ride, I bought data of 5GB for 175 which according to me was supposed to be taken from my airtime, I never recieved an sms, I thought maybe it was network problems, they will send an sms they didnt, this year I get deducted over R600 which is breach of our agreement, I have a legal binding contract with them to deduct 319 from my account until the 25th of April, when I called in on the 29th of January they told me I signed up to recieve recurring data, which is a surpise to me, I didnt sign up for that, I wanted to buy data which will be taken from my airtime nothing less nothing more, if I wanted a top up on my account I would have gone to them to add up if I wanted to, it seems Vodacom misleads customers with their promotions to milk money out of us, a week ago I bought data of 5GB for 7 days with R50, why was that one taken off my airtime? Why is it different from the black friday promotion?