WOW. Sorry to hear that. About all you can really do is make an appeal and hopefully get back in.
If not you might have to go the route of selling direct ad space or sign up for some affiliate programs.
To be honest you could earn more with affiliate programs and you wouldn't risk losing your account for invalid activity.
Also if your website has enough traffic you might try buysell ads.
A few alternatives to adsense are vertoz, infolinks, advertise.com although these don't pay out as much as adsense it's better than nothing.