How to confirm that a site has been banned !!! Is it by spiders stop visiting (for how long ?? ) or there is an indication that confirm that !
search on google "site:yourdomain.com" if your website was indexed before then this will confirm if your site is bann (if no results were found) from Google's index
Well if its a new site you can be indexed then not be indexed then indexed again, so it also depends on how long your site has been up. You can also check out your site on whois.sc to see if it has been blacklisted. Theres other possibilities also. If your site was down due to hosting or whatever for awhile it could be deindexed and you just have to wait for it to be indexed again. Only SURE way of knowing is to email Google and ask.