The email address you are using appears to already be linked to a SecureIdentity account. This may be the case if you share the email account with another person. In order to create your SecureIdentity, you will need to use an email address that is unique to you. So you might need to create your own email address.
If you believe that your email address is being used by someone who is not known to you then please contact us immediately on 0333 344 1679 and speak to one of our support team.