If, for example, you did not receive a purchase or if you've lost progress with paid resources on it, then please contact our support, we can add purchase manually or try to restore your lost progress.
When you have refund issues, please, contact the corresponding support service:

For Apple devices (iOS):
You can find a detailed guidance note on getting a refund following this link.

Follow the link if you want to get refunds on Play Market.
In the case of other app stores, we recommend that you contact the technical support of these stores for any refund questions.