My card was double charged by American express for the same air tickets, which I've requested to them to investigate by email and phone. During one week I've been requesting to give me any feedback on the matter, connect me with the person in charge, give me any deadline, but all in vain.
They expressively say that the management is occupied with more important matters and they don't have time to manage customer issues. Moreover, I'm contacting them on behalf of a big multinational company, and still they don't show any interest in approaching the customer's issues.
So be aware, that 1) American Express will do mistakes when booking your trip
2) they will not care about solving their mistakes
3) you will not be able to reach anyone who can take care of your issue
So use this esteemed agency at your own risk only..