MTN taking unauthorised insurance premiums

For some reason in the last few months I have had insurance added into both of my MTN lines. I didn't sign up for insurance on either of them, especially since one of them is a data line with no device. I have repeatedly tried to contact MTN insurance but I am hung up on every time after waiting forever to speak to a consultant. I want the money that has been taken without my permission to be refunded and the insurance to be cancelled.