Vodacom insurance ****

I requested cancelation of my insurance with Vodacom in May, they refused to cancel and debited my account for 4 months, everytime when I call they tell me its pending, they finally canceled last week, I requested that they refund the premiums I've been paying after I requested the cancelation, they are now refusing to refund my money. This is how they make money from people, they take long to cancel their services so that they keep deducting money from your account