If we are talking about AAdvantage miles - Check your BP. Is your AAdvantage number on it? Does it actually have the AA flight number on it or did CX switch it on check-in to a CX flight number? If the BP has a AA # and your AAdv # on it, it may take up to 2 weeks for the miles to show up after the flight. If not, or it doesn't show up, put in a claim for the miles on AA.com. Follow the links from the Customer Service option on their home page.