The service is still available...
I just googled the term ("plus non-stop" site:wind.com.gr) and here it is:
http://www.wind.com.gr/pages.fds?langid=2&pageid=1512
You can also go to the site and follow the drop down menus as follows: "For individuals->Prepaid->Wind F2G->Wind plus non-stop service"
Enjoy!