We had this problem a few years ago. One number for when we booked here in Aus and another for when we booked via the UK. And as bluemarble said, it had diff loyalty levels on each account. So, I had to talk with both Cunard, Aus and UK, and after a few months, they finally had me use the Aus number universally and that is where all my benefits are and we are finally Diamond members . So now, when I book I give them that number and have not had any problems. I have not booked via the US before.