Data contract

Vodacom is so bad. I made a contract upgrade of data package in which i have to pay R200. But then they added so many things which i was not aware of and now they say i have to pay +R3000. I tried cancelling the contract before an upgrade but they were not cancelling i had to upgrade because they were still deducting. This is so terrible. I cant owe close to R4000. This contract has been draining me and im still a student. I cant pay that much. The problem is that they dont even communicate other things. Im tired.