delaying cancellation to charge extra money.

When I searched for car rentals online, I found this third party website which is so cheap and booked the car to find that they deducted the amount from my card twice one for car rental and other for insurance separately. I reached them by phone and asked them to cancel my reservation they did not cancel the reservation. when I called them with option(4) on the helpline, no one attending, so I again dialed as an option(2) as a query, then they attended. they are not attending the calls when we are selecting canceling option.

Then I asked them to cancel my car reservation, they said they will cancel but they didn't, I did not receive any email confirmation on cancellation, I got a doubt and went online and canceled the booking, then I got email saying it was canceled, I am not sure why they did not cancel when I requested them to do so. Now I am waiting for my refund.