How to deal with the problem that they don’t attend

I had 2 car insurance n I cancelled the one insurance but they did not cancel it , they keep on debiting the money for 2 insurance for 2 months now so what is the point of cancelling whereas they keep on taking the money, why do I waste airtime every now and then while they don’t do what i say, I am disgusted and not happy at all😡they making me a fool that they cancelled one but you will be surprised every month end