Just in case some of you guys who allready entered the code and recieved the "processing" message: It was the same for me, and now I found my Genbo in the in-box, with 6 days to claim him.
Entering the same code again or asking for a new code at Prime Gaming doesn't help. So, before the 6 days to claim are over and you start a lawsuit against Plarium and Amazon, check your Inbox in the game!
Nothing there - checked various times, as the instructions state it will be delivered to Inbox!