Activate the Google Webmaster console, register and verify your site via meta tag. The console will tell you why your site isn't indexed yet, maybe was banned because of violation of their quality guidelines. If so, you may fix the issue and file a reconsideration request. I did it for a dropped domain that I've bought a few weeks ago. Google replied that they're looking into. Be patient, the process may take from several days up to several weeks .. or months. Best of luck
add your site to the Google listings by submitting the add url form on: google.com/addurl/?continue=/addurl then wait a little a couple of days so Google can crawl your site. Create a sitemap (if you havent already) and submit it to Google Webmasters Tools. Wordpress should have a sitemap plugin It shouldnt take months or even weeks (Google is getting much quicker at adding and finding new sites) if you use this process it should happen in a matter of days.
just do one simple thing create sitemap.xml and submit it too google webmasters tools i m sure that within one day your site will indexed.
Maybe you can wait little longer, as of now continue getting strong backlinks. Does your organic traffic affected too? I see you still have PageRank.
Have a nice site descriptions and meta tags, and submit your URL to google, here:- http://www.google.com/addurl/ Keep adding contents/posts And submit sitemaps to google webmaster tools
Sometimes google banned the domain due to some reasons and sometimes google banned the content of your site so before take some back links for your site if you get not good results then change the content of your site maybe some results you can get !
I login into the webmaster tool center and just find this "This site may be in violation of Google's quality guidelines. More Details Pages on your site may not appear in Google search results pages due to violations of the Google webmaster guidelines. Please review our webmaster guidelines and modify your site so that it meets those guidelines. Once your site meets our guidelines, you can request reconsideration and we'll evaluate your site. Submit a reconsideration request" What should I do?