For security reasons Schibsted limits changes to your primary email address for 72 hours. This is to prevent fraudsters logged in as you from being able to take over your account entirely.
You can change your primary email address any time if you still have access to that mail account. Schibsted will just send a link to the old primary email address where you can confirm the change.
If you receive notification that an unknown email address has been added to your Schibsted account, contact one of the sites you have a Schibsted account with and they can help guide you through the process of removing the unknown email address from your Schibsted account.
If this happens remember to change your Schibsted password as well as the password for your verified email account.