They make it almost impossible to cancel your contract

Where do I begin with these sharks? I have a contract that gives me 1GB of data a month and 100 talk minutes for about R128. Without warning, they restructured my 1GB of data, making most of it unusable for me. Forcing me to have to top up data every month. Now that I want to cancel, they want to offer me 11GB of data a month for R129. And also, I have to wait 48 - 72 hours for their cancellation team to call me back to cancel my contract - they refuse to do it today.