UPDATE:
Wasted half a day redownloading and reinstalling - no luck
Wasted another 2hrs waiting for support - tried to reset, was then asked for a product key for a trial - support advisor "added a new version" to my library, wasted ANOTHER 4hrs redownloading and installing AGAIN, only to receive the same error message...
Apparently I'ver used up a whole 7 days of game time since this afternoon, on a game that wasn't even in my library until then, despite the fact that both Origin and Battlelog show my free time has not started yet...
Time not started according to Battlelog: http://i.imgur.com/o57kbXL.jpg
Time not started according to Origin Client: http://i.imgur.com/0tWbbU3.jpg
Origin unable to activate - asking for a key: http://i.imgur.com/mqPWqNu.jpg
Time used error (despite the first two images CLEARLY showing this is not the case): http://i.imgur.com/nD5OITb.jpg
GG EA...