Daylight ******* by Cell C to gain profit

I really regret upgrading my contact with cell C because now they don't want to take responsibility for their wrong doings because they changed my top up contract to an open line contract without my concern now I'm responsible for the payment whereas no one ever informed me anything about the changes n from there they are disrupting my services whereas I told them that I'm willing to pay what we agreed on but not what I was not informed about. Every time I called them I'm getting a different story on the matter no one is willing to assist.