Google Crawler

We are a domain registrar and we host/park over 750,000 domain names.
Every now and then the Google Crawler decides to bury the machines that
host our 'parked' domain pages. We use robots.txt but that doesn't
help under these circumstances. I have tried sending a message to
Google using their web site. They don't have a NOC entry on either. Our only alternative right now is to block the
crawler at the router level.

Does anbody have a contact at Google or is anyone at Google listening?

Andy Ellifson