Basically, it is non-refundable.
Please make sure that PRO suits your purpose before purchasing.
You can check the PRO functions on the "Upgrade to PRO" screen.
Even in the free version, you can see the registration screen for the following functions, so please refer to it. (Cannot be saved)
Refunds may be granted if you make a purchase that you do not remember, or if you make a mistake in purchasing due to an operation error.
Please check Request a refund for apps or content that you bought from Apple.
As a developer, we do not have your billing information and cannot process refunds.
Contact Apple Support for billing details.