Hi Greg,
Make sure all of your themes and plugins are up-to-date. Also, try changing themes to the default theme and disable plugins one at a time. Does the issue go away? If so, note the plugin or theme causing the issue. Here are some more tips...
https://www.wordfence.com/docs/how-to-clean-a-hacked-wordpress-site-using-wordfence/
If you have questions on the Premium version, please email here:
presales [at] wordfence.com
Thanks!
Brian