MTN adding products and charging customers without their consent

MTN decided to add insurance for my mobile without my consent for more than R600 a month. Who gave them the permission, are they that desperate for business now they are adding things to customer accounts without checking with the customer first. Worse cause this is not even a new line, I've had this line from 2010 so this is not a mistake. Then last week a lady from MTN calls me and says I app**** for a new line online, which I didn't.