Hi Yannavong,
Thank you for writing to iTunes Store Customer Support. This is Rusty and I'm glad to help you today.
I understand that you were unable to received the item though you were already billed upon purchasing the item. I can understand the times are very difficult, let's see what we can we can do for you today.
Yannavong, we weren't able to verify an authorization from your financial institution, so we haven't received payment for order MHL55GV3QB. I would advise that you may need to settle the unpaid order on your account and as soon as this order is paid, you can purchase items with your iTunes Store account again.
Please contact the fraud or security department of your financial institution to find out why your card is being rejected. If they're able to resolve the issue, you should be able to pay for this order and then resume purchasing with your account. If they can't resolve the issue, you can pay for this order with a different credit card or with store credit.
To change your payment information, follow the instructions in this article:
iTunes Store: Changing Account Information
http://support.apple.com/kb/HT1918
Make sure that your billing address is exactly the same as your credit card statement. Even minor differences in punctuation, abbreviation, and capitalization can cause payment errors that might prevent you from using the iTunes Store.
Moving forward, you can also pay for this order by redeeming an iTunes Gift Card. See this article for more information:
iTunes Store: How to redeem a code
http://support.apple.com/kb/HT1574
After you redeem the code, the unpaid balance of this order will be deducted from your store credit balance.
I hope this helps. If you're still having issues paying for this order, please let me know. I'll be happy to help.
Resolving your issue is important to me, and I look forward to your reply. Thank you for choosing iTunes!
Sincerely,