Spent $49.99USD in-app and received nothing, but refund request denied.

"How do I get a refund for an in-app purchase that gave me nothing, when my refunds have already been denied twice?"

I recently spent $49.99USD twice in an app called Love Nikki. When I had first purchased the item in-app, I used iTunes credit, and did not receive anything at all. I had to purchase it a second time using credit card information instead. This totaled up to $99.98USD spent when I had only received 50 dollar's worth of in-app items. I attempted to refund the first purchase (the one that did literally nothing) but was denied even after appealing the decision. In the picture album, the first image is a text of what I exactly said to Apple; it may have been overly detailed, but I made sure to say, "I received literally nothing for this purchase." Since it did not suffice, I tried contacting the app developer for assistance. The app developer's support team informed me that they only detected one purchase on their end, could not provide the other purchase, and that I would need to contact Apple again, as shown.

How do I refund an in-app purchase that provided exactly nothing, when I am unable to make any more appeals for the specific purchase? I had to purchase the same item twice due to being on a time limit, but the first purchase, I reiterate, did not give me anything in-app at all. The Love Nikki support team advised for me to "call" Apple regarding this refund, but how do I do that? Which number would I have to call in the USA for refunds? Or is there any method of chatting with any other Apple support members? I am reluctant to refund the second working purchase, because it provided me with the product that I actually wanted, and refunding it may reverse many unobtainable items I had achieved afterwards in-app.

Love Nikki said that Apple "charged me twice on accident" which is both technically true and untrue. I deliberately attempted to buy the item twice, but only received it once, and was not refunded for the first in-app purchase that did nothing. I have read other accounts where people in my exact same situation had their refund swiftly resolved, or even people abusing the refund option and getting away with it. I am confused as to why I can't appeal the refund denial when my purchase of $49.99USD did exactly nothing, which to me seems like a valid reason for a refund. My iTunes account is also in good standing, considering that this is the only situation where I suppose I would be requesting a refund. This is a situation that handles sums of money on a scale too large for me to ignore.

Relevant images depicted in the link below.

https://imgur.com/gallery/5GZV0MS

Aug 15th, 2020 - Bought two in-app purchases; only received one

Aug 17th, 2020 - Requested refund

Aug 18th, 2020 - Appealed denial

Aug 19th, 20th, 21st, 2020 - Contacted app developer, and the app developer instructed me to contact Apple once more