I orderd a new car that will arrive in about two weeks. In preparation for payment I called Amex to be sure that they would back me up should there be a problem with paying in full with their credit card. What I was told surprised me and I wonder if I got the correct info. They said that if a maximum amount was set for all credit cards (Visa, MC, etc.) then they can set a maximum for Amex as well. Only if they allow full payment for the other cards do they have to allow full payment using Ames. Furthermore I was told that there are different merchant agreements with different vendors and some of these agreements allow for minimum/maximum payments. This is in direct contradiction to what I have been reading on this thread and I wonder if I have been given the correct information. Is there a particular Amex department that I should contact? A legal department? Any and all suggestions will be appreciated.