What happens if you are disputing an in-app purchase with a vendor that is in CHina and is not understanding your issue and refuses to add the disputed purchase or refund the purchase?

I made an in app purchase and the game (Happy Farm) crashed but I completed the purchase on my iPad's Home screen because the Confirm purchase window popped up before I could relaunch the game. When I launched the game the purchase (which was Gems) was not showing so I took a screen shot of the game window showing 211 diamonds, which was the amount I started with, (the purchase was for 258 gems so my total should be 499). I then took a screenshot of myhome screen showing the time of day. I went back to the game repurchased the same amount, the app did not crash this time and I was credited with correct about of gems 211 +258 = 499... Took a snapshot of that screen. went back to my home screen and took a screen shot to show the time again. Well after sending Happy Farm all of this evidence, they responded that they gave me all the gems and I just used them all. I don't believe that they understand that my app crashed and during the 1st transaction and I clicked the Buy button (in the Confirm purchase window) on my Home screen not in the App, got charged but did NOT recieve the gems when I relaunched the app. I have more proof than most people and they are still calling me a liar... I need intervention from iTunes App store and I don't know how to get them to mediate this dispute. Do you know how I can get in touch with the App store?