Please read this Google Play User Guide:

Our own policies and legal requirements for a refund.

All our applications have a free trial period or free version "try before buy" and the Google Play allow 48 hours period for a refund if you make a wrong purchase, this is the main reason why we are doesn't refund after purchase.

But we can refund at the few cases:

- The application doesn't work on your device, you can present the proofs and we can't fix the bug after you contact our support team.

- You are making the double purchase of the app, 48 hours is gone after purchase and Google can't refund, you can provide the purchase information of the double transactions.