Your account client ID will have been emailed when you signed up. If you have forgotten it, in the first instance refer back to that email which will include 'Pinnacle Sports' in the subject line.
If it's not helped follow: www-pinnaclesports-com/Secure/Fo --- entID-aspx
Can I change the email address registered to my Pinnacle Sports account?
If yu want to change the registered email address of your Pinnacle Sports account, please contact pinnacle Customer Service Department: [email protected] using the email address currently registered to your account and include your Client ID.