Have you checked the URL on the normal site checking tools we use,
http://sitecheck.sucuri.net/scanner/ -
http://urlvoid.com/ etc. etc. ?
Currently the on-line contact form,
http://www.avast.com/contact-form.php?loadStyles doesn't cater for reporting Undetected malicious/phishing sites only reporting FPs on sites.
Since avast doesn't specifically have phishing sites on the VPS only malicious/infected sites, there isn't a specific way to report them for inclusion in the VPS for Network Shield.
Also see
http://forum.avast.com/index.php?topic=82635.0, extract below.
Reporting a phishing/malicious/hacked site not detected by the Network/Web Shield/s:Essentially it is sending an email to virus (at) avast (dot) com (no attachment as there is no physical file) outlining the issue and giving the URL in the body of the email.
The email Subject is probably more crucial as I would say it still has to be called 'Undetected Malware' for it to be filtered within the receipt system for action. I would go further and include 'Network Shield' in the subject to further define the problem and possibly attract attention. So the subject would be something like "Undetected Malware - Network Shield - Phishing/Malicious site" (whichever is applicable), without the Quotes.