We are sorry that you are not satisfied with the app. You can refund via the Google Play site, please read their support page. You also can send a request to firstname.lastname@example.org. We do refund for a purchase made no more than 30 days before the request date. Please send us your purchase id (a string like GPA.123-456-78910). To find it, look at your purchase history. Our support is not 24/7, so please be patient.
Please note that if you made a refund, it can take some hours (or even days) until the money reaches your card/bank/etc. The time depends on your bank, not on Google or us.