Refunds are available within 7 days of purchase if the app does not work as described.
Email nova.team.support@gmail.com with the email address you purchased with. Telling us what went wrong helps us fix it, but it is not a condition of your refund.
Purchases are processed by Gumroad, and refunds are issued back to the original payment method through Gumroad. Once a refund is issued, the associated license key stops being valid for GO or PRO features.
Nothing here limits any refund or cancellation right you have under the consumer law of your own country. Where that law gives you longer than 7 days, that longer period applies.