I'm sorry to hear that the rubber is detaching on your SoundLink Around-Ear headphones II.
As this is a cosmetic issue, we are not able to assist through the Bose Community. I'd highly recommend that you contact your local customer support team and they will be happy to advise you of the next steps.
Global Contact Us > Select your country > Scroll to the bottom of the page > Click 'Contact Us'
Please let me know if you have any further questions.