I flew business class with Air Canada from Caracas to Paris via Toronto, and then onward with Vietnam airlines to Hanoi. I have redeemed the miles from the Paris/Hanoi segment, but when I tried to redeem the Air Canada segments with Lufthansa Miles and More (Star Alliance), it says "flight already credited", which is hasn't been. Who should I take this up with? Air Canada, Star Alliance? All suggestions would be very much appreciated.