Sorry to hear your helmet doesn't fit, returning your helmet is super easy! You would need to first ensure that you are within our 14 day returns period, you would also need to ensure that the items have not be worn outside and are returned to us in the same state in which they were delivered to you in. If you head over to the link below, you will be taken to our returns portal.
Follow the steps on this page, if you do get stuck or require any additional assistance then be sure to drop our Customer Experience team a message and we can assist you with anything you need.