I have sent a number of wire transfers to AMEX to balance my account through the years. My assumption is that you are trying to pay into a U.S. dollar AMEX account. While you obviously did not provide wire and account details, my assumption is that AMEX provided you a bank with an ABA (American Banker's Association) number in New York and a specific bank account number to pay into. Likely they will have asked that you provide information with the wire regarding the AMEX account number that you wish to credit. Usually by wiring the money, if you have a helpful US bank, they should be able to check with their contacts at the FED and the transfer should be nearly instantaneous with a confirmation provided the same day. Late afternoon transfers are still dicey.

If you used a wire transfer from a US account to AMEX's US bank account in New York, my guess is that the hang up may have been on the side of AMEX. The money likely went into a general account and it would have been up to AMEX staff to actually correctly credit the funds to the correct account that you wanted to pay. They may have seen your SSN or some other identifier and simply deposited the funds into the first AMEX account you have that showed up on their screen. Obviously, you should have a case to have them refund any late fees or other problems that their mistake may have caused.

My guess is that there is more to your story that meets the eye-- if you are paying from a US bank account to credit a US AMEX card, I would think you can simply use their online bill pay service as it credits the same day. Admittedly, perhaps they wanted confirmation of same day funds receipt in which case I understand that you may have made the wire transfer.

In my case, I have made important large payments to the International Dollar Card in London using a Federal Reserve wire transfer from a US bank to IDC's New York bank account. In those instances, after I received confirmation that the funds were transferred, I had to pass IDC the information so that their payment section could search through their US bank account deposits to actually confirm receipt of the FED wire transfer.

The transfer may be instantaneous but AMEX still has to deal with the credit in a bank account where it is likely receiving hundreds of credits. Hope my experience helps you decipher how to handle your situation better in the future.