I don't like your app, give me a refund!
Within the first 48 hours after purchase, the easiest way to get a refund is to go here
and select "Request a refund".
If you want to get a refund later, please send me the "Transaction ID" starting with "GPA..." which you can find either in the receipt Google sent you by email when you bought the app or at https://pay.google.com. I cannot perform refunds without this ID.