With our advertising programs we strive to create an online ecosystem that benefits publishers, advertisers, and users. For this reason we sometimes have to take action against accounts that show behavior towards users or advertisers that may negatively impact how the ecosystem is perceived. In your case, we have detected invalid activity on your AdSense account and as a result it has been disabled.
We are limited in the amount of information we can provide about your specific violation. We understand that you may want more information about your account activity. However, in order to protect our proprietary detection systems, we are unable to provide further details.In some cases publishers can make significant changes to correct the violation and are willing to comply with the AdSense program policies. For this reason, we offer an appeal process as an opportunity to work with you to resolve the issue. Please be sure to provide a complete analysis of your traffic or other reasons that may have generated invalid activity in your appeal. Submit your appeal using this form and we will follow up accordingly. Before submission, please review the list of the top reasons for account closure.
Thanks for your understanding.
The Google AdSense Team
In other words they closed my account because they suspect invalid activity, but have no idea where it is coming from, then ask me to be understanding,