Gift card not received

So I have two app store accounts. One is for the U.S. app store and the other one is for the Chinese app store. About two weeks ago, I sent a $15 gift card from my American ITunes account to my Chinese ITunes account. Then, I immediately received an email from apple saying that they charged me $15 on my credit card and there was the receipt. I then went on my Chinese account to check the balance and the balance was still zero. I thought I should be patient and waited a day to check again but it was still zero when I checked it the next day. I went on internet to look up the reason and found out that you can't send gift card to an ITunes account of a different country. So I changed the region of my other account from China to US but still didn't see the money. SO I would like to know where my money went and I received the bill from apple yesterday so Apple has definitely charged me that $15.