Keep trying. Seriously, in June we planned a last minute trip. Started planning one Sunday. Arrived in Orlando the next Sunday. I was practically on the phone with Disney Dining at least 4 times a day during the week of planning trying to get CRT ressies. When I finally got the reservation, I don't know who was happier, me or the CM who got me the ressie. I think it also helped that I was a little open. Since eating at CRT was our priority, I was willing to move other ADRs around to get it, and I told each CM that when I called. I'd have taken breakfast, lunch, or dinner on any of several days.