Hi there, thank you for your post on our forums!
We understand you're having some issues redeeming your Batman: Arkham Shadow incentive, please make sure to try redeeming this both through your headset and through your Horizon App.
To use your headset to redeem the offer, go to the Meta Quest Store in the headset to redeem the game. Otherwise you can do this on our app by going to “Payment and extras” after your setup, and you will see the offers there.
Please note: you will need to be located in one of our supported countries, detailed here, and you will need to add a payment method to redeem the free game.
If neither option works, please get in touch with us over Private Message by selecting our name to get to our profile page, and clicking "Send a Message" to privately message us! Please remember, you must be signed into the community first to send us a private message.
We hope to hear from you soon!