You'll note in my response that I said that I did, in fact, have a productive email exchange with Herbie's before my order. And again, double check the email address that you're using to make sure it isn't one of the discontinued herbiesaudiolab.net addresses. You want either "info" or "audiolab" @ "herbiesaudiolab.com." I believe that "info" is what gets used when you submit a question via their webform, but "audiolab" is the address from which I've received responses.
(I had this happen to me with SonicCraft. Spent a few months being frustrated at Jeff's lack of response after a history of great responses, only to discover that I'd missed an email address change. Shame on me.)