Wiped from Google Top 50 and Need Diagnostic Help

[SpotColorMarketing53]

Hey All,

On the 4th of January our site (http://spotcolorstudio.com) Webmaster tools showed a massive drop in the number of impressions we're getting from Google.  We went from over 500 to around 100 and we haven't recovered.

That week's SEOMOZ keyword report showed we were wiped from the Top 50 for everything we were tracking except our branded terms.

I've seen no indicators to why this might have happened. Our Domain Authority hasn't changed.  I haven't received any malware notices in Webmaster tools.

GetListed.org displayed our Google Places listing as not present despite being able to click through and see our listing displaying as "active."

Is it possible there's something wrong with the DNS that I'm missing?

What could cause a complete wiping like this that wouldn't trigger an alert in Webmaster tools?

Any help, guidance or suggestions will be greatly appreciated!

Craig

[SpotColorMarketing53]

Also, around the 4th, the total pages indexed dropped almost in half.  What could cause Google to drop the total number of indexed pages?