Did you ever clicked on your ads ? Or said your friends to madly click on your ads ? Or break any adsense privacy policy ...... If you didn't do these jobs, so you still have a chance to get back your account. Go to adsence appeal form and honestly fill the forms then send it.
it was clearly stated that your AdSense account has posed a significant risk to our AdWords advertisers. Mean your site is providing low quality click
you don't know why because they don't want you to know why, so you can't tell other or try again yourself with new account which you're not supposed to open anyway..
Must have been something about the content on your site that Google did not like. Or your not giving us the whole story as to what you were doing to drive traffic to your site or how you were placing your ads to get clicks.