Aren't these two different things though? When you submitted through the form here at Scirra.com, you were pretty much guaranteed a payment for your game. As long as they accepted the game of course.
I think the general tizen challenge with 6000$ in prizes is a separate thing here.
I also submitted one game and the last message I received from appbackr was saying that they would pay me when they confirmed the validation of the game on the tizen seller store. The game has been approved for a while now without any further word from appbackr. And my contact there doesn't seem to reply anymore. Weird.