If you haven't tried already, and the balance is $0, try a GW or DV (on this paid CA).
If you google the CA, eventually you can find a name. If no name and the CA's name is vague, then try googling their phone or fax or even address. You can also check the whois domain registration for the site and pull off a contact name or two including phone numbers. Use that to backtrack and try googling those.
Eventually, you'll find a contact name doing this. Typically CAs will join CA associations and attend seminars. Most of this info is available on the web. When CAs go to these things, the company Pres or the main contact within the org. will attend. It is very easy to lift an e-mail off those lists.
Also, CAs will join civic or chamber of commerces. You can easily find info in there.