high account

Last month I was contacted for an upgrade and offered a cheaper contract that at present. I also went onto my phone and cancelled all the addons that I was paying for. Low and behold I still got an account for over R744.00 for the month. I seriously cannot afford this and my phone is connected to wifi most of the time so there shouldn't be extra charges. It really just seems that the cell companies charge what they want and the customer just has to foot the bill. No matter what complaint you have.