Bad service from Rain service provide

Rain internet service provider is a ****. We have subscribed for R250 unlimited internet usage. The terms I am concerned about is using internet between 11pm-6pm which is unlimited and we insure that between 6pm-11pm we switch of the wifi gadget but the bill comes back with over R250 charges. We have asked for the breakdown statement last month but no response and again this month we are charged more without any explanation.