AMEX is both really good and really annoying with this. On the good side is that they'll try payments up to three times, most other lenders do not do this. However, during the re-presentment process your card is indeed blocked until AMEX can call your bank and verify that the funds are now available to clear.

Note that it is not technically a returned payment until after the third failed attempt. This is what causes the big red flags and often causes them to close accounts. With other lenders, once its returned the first time that is it. Note that if your payment is initially returned as "Account Frozen/Closed" they will not try twice.

Another thing to keep in mind is that after even one payment issue (such as being returned once and clearing on the second attempt), they are likely to start putting payment holds on your account. This can be very annoying as you have to call them, then have a conference call with your bank, to clear the funds.

While I understand the need for there to be some risk management involved, it would make sense for them to not remove the payment from the balance until, perhaps, the second attempt. In today's day and age, with debits, check holds and everything else, I'm sure it is very, very common for payments to return once in error then clear upon the second try. What makes no sense to me is blocking the entire card. If, for example, I have $5000 credit available and a $100 payment bounces due to an error, why block the whole card (in addition to every other card I have with AMEX) and not just remove the $100 from the available balance?

In my case, I make a ton of payments (5+/week) and they oftentimes they'll hold every payment for the last 14 days without notice, even when these payments were not previously held. It is a very stupid, annoying and dumb process. This requires you to wait until business hours to have AMEX call your bank to verify that the past X payments have cleared. Then, after verification, if you make another payment the following day, their system will place all of the payments back on hold and you have to restart the process.