Google Adsense offers an avenue to setup a website and start making money off it right away in a simple process; however certain wrong moves as an Adsense user can get you banned. This can prove catastrophic if you run your site on a limited budget and use your Adsense earnings to compensate for site maintenance and hosting costs. If you get banned, there is little light at the end of the tunnel but if you address the situation properly you might be able to have your account reinstated.

The first thing most banned users would do is flame Google about their evil practices on webmaster forums when usually the user would be at fault. Google never bans your account for no reason even though several banned users might claim this which is probably false and stated out of frustration and envy. Instead, you should look to identify why your account was banned. Here I should mention that Google may not be very transparent about the reason except with an acknowledgement like 'Your website is a potential threat to our advertisers' or a variation of that phrase. So the first step would be to review your website and look for any loopholes that might have been breaching Adsense policies.

Common reasons for getting banned include fraudulent clicks, inappropriate content, enticing the ad to site visitors with a byline like 'click this' (etc) and also the absence of a privacy policy stating that the ads served use a cookie to store some user information to display the ads. You need to look through the terms of service properly and make sure there is in fact a reason that your account was banned, once you identify the reason (no reason isn't one), fix the issue if it is something that still exists and mail them stating you have taken care of it, if it is something like invalid clicks you will need to assure them you will do everything to make sure it won't happen and chip in some small talk to support your email. After this all you can do is wait.

If you do not receive a reply in a month, you are probably out of luck but you can try setting up a new account with entirely different details (including IP, browser, OS, screen resolution and anything that can be identified by tracking code for that matter if possible), if you can register it with completely different credentials you might have yourself a new account and technically it won't be against the TOS too.

If all fails your best bet would be to use an alternative to Adsense, there are literally hundreds of similar money making alternatives which can generate revenue at least close to what Adsense would bring.