Bad service after upgrade

I recently upgraded end of November for a data line, for a monthly bill of 199-00 per month. This upgrade was online, when it was delivered the device it doesn't specify anything. To my surprise this line keeps usage of data after the one I subscribed is finished. I only realized when I was checking balance since I was in the assumption that it will cut of data usage once the one I subscribed is finished. I phoned customer care and told it's an open line. My question is why I wasn't made to be aware of this during the upgrade. Now the bill is above what I can afford even tried to liase with their accounts department to allow payment instalments. Vodacom is *****ing from me and now I see the bill has content subscriptions which I never did and want me to pay, which makes me think letting the line run even the subscribed data is finished its a way of capitalizing on customers. Now I don't trust online upgrade. When they deliver the device they don't bother to sent a contract explaining how it works, furthermore no one from vodacom called me to clarify this after I did request an upgrade. This is a totally reap off. These customer service people are useless you phone and phone, they refer you yo accounts and it's the same thing. I have been a loyal customer for over 10 years and it means nothing. I am totally disappointed. Wish they cancel that bill because it's there fault for not explaining during the upgrade. Worse part they don't bother to even email you a contract to go through or give explanations, they are just quick to deliver. This is a terrible service