If you still want to return the app. All credit for any app product is always done thru the App Store. You would have to contact apple for a credit.
How to get a refund using your iPhone or iPad
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.
You should hear back from Apple within a few days to a week with whether your request for a refund is approved.
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