You can request a refund using any web browser:
- Go to Apple's problem reports page: http://reportaproblem.apple.com/
- Login with your Apple ID and password.
- Select the Apps tab.
- Find the purchase you want refunded.
- Select "Report a Problem" to the right of the purchase.
- Select the reason you want the refund.
- Fill in the description and select "Submit".
iTunes and App Store refunds typically take a day or two to process and you might get contacted by Apple support to verify the reason for the request.