Vodacom gave me data bundles without my consent now I have to pay a huge bill and they refusing to assist me

I have a cellphone contract with Vodacom one of their consultant called me offering me 1G data for R140 because I was paying R150 for 10G on my contract that just ended then I refused ,then before my debit order goes off I checked my bill. Only to find out they included the 1G data bundles without my consent now they are giving me run around refusing to fix the bill for me. I didn’t give them permission to do that because it’s expensive. It’s been 2 months trying to resolve the problem no one is willing to assist me. I’m so disappointed with their poor service I wanted to give them zero stars they don’t care about their clients all they care about is money