Violating customer rights

Hi I have a issue with this Mondo Team company ,I received a call from one of the consultants n they told me that I've been chosen for telkom 1gig data and i would be paying R150 monthly for 24 months ,which they said the contract will be active as soon as i start using their sim card then i told them i dont need any contract with telkom because i have a contract with cell c ,the consultant told me that i wont be charged while i haven't used the sim but as i check this Mondo company have been taking money from my account for more than 4/5 months now of which i really dont understand why because i dont have any contract with telkom . I also called the customer service and they told me to go get an affidavit and send it to them of which i did and i even received a case number for my issue but even today im still receiving mail notes saying that i owe R1 978,76.. So im really tired of calling you guys and its about time i take further steps on this case . Regards Gift