Realm not cancelling

I started the free trial using my Xbox gift card money and after a week I cancelled it by clicking the subscription and stopping it. When I didn't see my realm, I thought it worked and I cancelled the subscription. A few months later when I wanted to buy overwatch because it was on sale for cheap, I checked my account balance and saw it was at zero. I wondered, where did it all go? So I checked my history and saw the subscription never actually cancelled and for months it has been charging me so I am not happy and want a refund.