Dear User, sorry to hear you are seeking a refund.
May you give our Premium features another chance? They are designed to help you reach your goal faster. Also you can stop your subscription anytime you want.
However, if you decide to proceed with getting a refund, please contact Google Support directly. You are eligible for a refund within 48 hours since the moment of purchase. Otherwise, reach us via in-app Help Center (in Profile settings) or at firstname.lastname@example.org.