Free Version Of Wpdownloadmanager is adding Sitewide link on Blog

Hi i have used your free version my blog is totally destroyed now. Wpdownloadmanager pro is adding a do follow http://www.wpdownloadmanager.com link on every page of the blog.You cant able to see that you can check buy going to source page or on tools like ahrefs.They are not even mentioning they are are injecting code on thier plugin.