It looks like only the recipient can return the gift for a refund. I had thought it was the sender but apparently not.
Oculus have an app gifting page which explains about the processes including a note on what to do if the gift went to an incorrect email address... namely to contact support who will have to manually sort it out.
you can contact them here...
Note also that if a gift isn't redeemed within 30 days, it'll automatically be refunded but I wouldn't wait for that just in case the email you sent it to happens to have a headset!
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