If you do a search for your site with site:YOURSITE and you can still find your site, then your site has not been banned, it possibly means that your site has been penalised, as some of your links might have been penalised and you followed suit
I was once banned but for a different reason. The replies to this thread are quite informative, it will keep our eyes open on how we interact with google.
any websites i have seen that have been banned usually dont come back again, thats if the site has been banned completely and not just got a temporary punishment
When you search on Google for yoursite.com and it is still showing your site then there are 2 possible things 1) Your keywords have dropped down because of excessive link building. But it is advisable to keep on building links but slow the rate down. It has happened with me many times but when the keywords came back into rankings, they came back with improved rankings. 2) Google has banned several tools, the tool you are using might also be banned by Google.