Charges clients extra without letting them know

I changed my medical hospital plan after researching on Discovery's website. it did nit state that there would be extra charges associated with the hospital admissions. And then I phoned to make sure and there are extra charges that are NOT stated, so I immediately tried to change it back the next day. But it would not let me. And calling the call centre will not let me either. Now they want me to pay an extra R7500 for hospital entry without any information on the site. If you are going to charge extra you need to let your clients know in the information brochure, otherwise it is unfair practice. Please allow me to change back and correct your information literature. Regards,