Headset Pairing and Assignment

So I just recently bought a refurbished wireless headset, (Razer Kaira Pro), and the day I bought it I paired it to my girlfriends xbox one, and it assigned to her account. I’m now at my own house 2 days later and using my own xbox but I’ve tried 50 times and can’t get the headset to pair to my xbox. even though it paired to hers perfectly on the first try. and I don’t know if it’s an issue with my headset itself, or an issue with my xbox and the headset being assigned to her. can someone help me so i know if i need to return the headset? thanks.

:)