Refund of a subscription denied

I downloaded a free trial of an app called bank note scanner. It did not work properly. I cancelled the free subscription within 30 minutes and was then charged 4999 for a yearly subscription. I did not authorize. I followed the process of requesting a refund only to be denied . I challenged only to be denied again once I contacted Apple I was told that if you are denied a second time there is nothing Apple can do for you. That that is our policy any help would be greatly appreciated. Thanks everyone