Apple hasn't built any links to problem reporting into the iTunes Store or App Store apps, so if you're stuck using the web on your iPhone, iPod touch, or iPad as well. If it's more convenient, you can go directly to problem reporting via your email receipt.
- Launch Mail from your Home screen.
- Search for "Your receipt from Apple" if it's not immediately visible.
- Tap on the receipt for the purchase your want refunded. (Unless you remember the date, there's no way to tell which receipt is which unless you tap it to open it, so you might end up tapping a lot...)
- Tap Report a Problem next to the purchase you want to report. You will be redirected to Apple's problem reports page.
- Enter your Apple ID and password when prompted.
- Tap Choose Problem and select a problem from the menu.
- Enter details for your problem, then tap Submit.
You should hear back from Apple within a few days to a week with whether your request for a refund is approved.