Installed, set up account with DupeOff. Plugin information says 5 free checks per day with WordPress plugin. Ran the check once, ended up with a blank page. Tried running it again and was greeted with a box saying I only got have one free check per day and to purchase more.
Went and logged in to the site, it says we have 0 free checks remaining and 0 used. There's nothing in the check history tab either.