Thank you for reaching out to the community regarding your Noise Cancelling Headphones 700. I am very sorry to see that you are experiencing some discoloration in your headset.
For support regarding this, please reach out to your local support team for further assistance. To contact your local support please follow this link, select your region and scroll down to "Contact Us". There you will find the appropriate contact information and an agent will be happy to get this resolved for you.
If you have any further questions please let us know.