Hello
This will need to be done via Microsoft billing support, not community forum here.
To get help, open the "Get Help" app on your computer (just search for it in the Start menu). or 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. Because such license purchase typically is not refundable, but mistakes happen. Make sure you explain that to them and they usually would make exception for you.
