How to get phone support with an unrecognized email address?

When I call the Intuit phone number for support, it does account validation. Because I use the online service, it wants to validate via email; spelling out the username portion and saying the domain name.

Unfortunately, despite trying 6 times, I have yet to have it come close to recognizing my domain name, and it doesn't like it when I spell the domain. I can't get any phone support because the system isn't smart enough to validate me, but there isn't any other way to validate as far as I can tell.

Any suggestions for getting around this Catch-22?