Epic Games does not have the ability to process refunds for purchases made
with third-parties. To request a refund for a purchase made through the
Windows 10 App Store, please contact Microsoft Support. You can find their
support page
here.
To request a refund log in to your Microsoft account. From there navigate to
Payment & Billing and open up your Order History. After that select the
app or game and select “Request a refund.”