This may sound very stupid. I ended up trusting a client and taking on work without any upfront fee. In fact we worked out a 15 day payment cycle. Although I was a bit apprehensive I took a bold step and am now kicking myself because he just disappeared off the screen. I have found some of the work already posted on websites. Are there any Indian writers out there that can help me (this is because both me and the client are India based). I would truly welcome any inputs from anyone else too. No phone contact. I only have email ids. He posted a classified on Craigslist and that was it.
I think most web designers have been in this situation. Do you have control over his domain name? if so that is the only real way you can hold him to ransom for the money he owes you. If he does not care about the domain then there is not much you can do without his contact details unfortunately.
There is something called DMCA.. copyright act.. you can try this out, may be. i'm not sure though. google it out.
Send a DMCA notice to the hosting company that is hosting the site. And also another notice to Google. You should be very careful--there are many scammers out there. Trust no one.
You can report to Google to remove pages that contain your copyrighted content using this link: http://support.google.com/bin/static.py?hl=en-gb&ts=1114905&page=ts.cs&&rd=1