I need a refund on fortnite crew for Nintendo switch

You need to contact Nintendo. It has nothing to do with Xbox.

But not for Fortnite because my friend has a Nintendo Switch and he doesn't need to pay the online subscription to play Fortnite for free.

Hello,

Thank you for posting in the Microsoft Community.

You can subscribe to Fortnite crew inside Fortnite from either the item shop or battle pass tab.

Your subscription is associated with the platform on which you purchased it (your “primary platform”) until it is cancelled. the Fortnite crew subscription is not transferable between platforms.

To claim the current month’s crew pack, you may need to log in from your primary platform if it has been more than 30 days since your last login from that platform. assuming you’ve done this, you’ll receive the crew pack items automatically as long as you’re an active subscriber.

Be sure to choose the platform (e.g., playstation, xbox, nintendo switch) you purchase your subscription on carefully. you’ll be able to access the crew pack items you receive from the subscription across different platforms, but the v-bucks you receive may not be redeemable on other platforms.

Source: Fortnite Crew | Monthly Subscription - Fortnite

If you are having issues with your Subscription, it would be more beneficial to open a ticket with Epic Games with your concern.

Thank you for sharing your feedback with us. If you need further assistance, please let me know.

I don't think you can refund fortnite crew

It doesn’t let me purchase the Fornite crew?