I get banned long time ago and it just happen. I visit my page and see adds like it was when I apply to adsense. I check my email and was surprised when I see my adsense account was banned but I did not do anything wrong.
For 3 months adsense code was on my page without touching and suddenly get banned.
If happen to you, sorry about it but nothing much to do...

They will confirmed you through your used gmail account I think the only way to fix it is to contact the admin.

But the question remains, google bans without giving a proper reason.
How can someone be careful for future when don't know about the mistake?

When they will ban your account they will send you email and ads will be stopped displaying on your blog , website or page where you have kept the ad.

Contact them at adsense-support (at) google (dot) com. In most cases, they do respond, but your query may be ignored if they think it isn't necessary to be answered. They just say "SORRY" and say thank you in advance for your peaceful "UNDERSTANDING"

Well, Adsense have the Policy page, Terms and condition page, And page which shows what kind of websites can not be on adsense. .. I believe you have used other website for the signup and using the adsense code to another website, Hence 90% chances to get banned...

You need to read the adsense terms and conditions and follow the policies and make sure you do not violates the rules.... I have an adsense account since 2004 and since im using the same account..

Your website content can be the problem,, Make a website with rich unique content, Authority website... And make sure are not violating the rules by the content of the site or anything like using adwords and targeting the adsense site, or buying some other paid advertisement for the site on which you are using adsense... There are small small small thing that we need to take care off.

ADSENSE IF GREAT !! And my source of imcome from last many years