go to google webmasters program, or google sitemaps and you have to find there a link to resubmit a site, which was banned from google. It is a contact form especially for these kind of problems. I had a problem once with a website which was banned from google index due to a illegal line in the source code and after i have fixed it, i went there and resubmited and it worked just fine in a couple of days. I found the link https://www.google.com/webmasters/tools/reinclusion?hl=en
you should have a gmail account i think to acces it.