Hello,
Windows license purchase is typically not refundable. But if you purchased by mistake, chat with billing support. They might make an exception for you.
Go to https://support.microsoft.com/contactus, Type "Billing" and press Enter. On the next screen, click "Contact support" at the bottom of the page, then choose "Windows" > "Manage my subscription". You’ll then see the option to chat with a Microsoft support agent who has access to your account to help review the issue.