How to contact a human being at Google AdSense?

I'm trying to sign up for a Google AdSense account but I get this error message that "You already have an AdSense account".

I'm 100% sure that I don't have any other account. This is my first one. I don't even recognize the email address that they claim is associated with my duplicate account.

The frustrating part is that there's no way to appeal this. Not a single email address or phone number is provided on the website.

Is there any way that I can contact a real person at Google AdSense?