Very same issue right here with me.
Made a thread about it in the Ghosts PC forum section (One of 500 - Prestige Edition: Question | Community) and tried to contact Activision, but as it turns out there is hardly any way to actually reach someone over there. The only email adress I found who could possibly know about it is the PR manager Christian Blendl and I have not recieved any response, nor even the notification anyone actually opened my message (went straight for the spam/wastebin I guess) in weeks.
With now five days until launch and no idea whatsoever what Activision is doing about that promotion, whether there's even going to be an option for PC gamers (as there's no PC Prestige Edition, at least not in Germany) or not, I can't help but think the whole promotion has gone to hell. I certainly know I feel like they completely forgot about the whole thing.