I didn't receive my in app purchase and Apple refused to refund me. What should I do?

I purchased some in-game gem packs, but never receive it. I go to my receipt and report the problem twice, but Apple rejected them all. Right now I don't have any way to get my money back! Is Apple allowing the merchants cheat their customers like that? Grab my money without delivering the items and refuse to refund? That's how Apple makes money?