forge.joomlapolis.com/projects/cb-cbconnect
Via download, under professional go to the incubator forge area then log in and click on the plugin name in the left column. Pretty cumbersome, but it will get you there.
By the way - Google and Facebook both will end this authentication service end of the year as I have learned aftet paying the same route that you did... kind of disappointing seeing them advertise a functionality that will go away in a few days.
For me, the cb-connect was the only reason to upgrade to the professional version and I kind of regret that decision, especially as the 2.0 version is full of bugs that make it even worse than the products you get in the advanced section (e.g. e-mails incorrect, redirect does not work). I am pretty unhappy and expected more for the money.