collect contact e-mails from accounts ?

Anyone know a script or a easy way to collect all cpanel contact addresses ?

My "problem":
Many of my clients set contact address in cpanel but "forget" to change the email
in my billing script so the invoices is not coming through.
I then need to check which server a account is on, then login to whm and list the account to see if the have another contact email there I can use.