Amex, like other credit card companies, has a maximum credit limit they will let you charge (even if you're paying it off every month). Recently, I got an email from them saying they are reducing the amount I could charge by several thousand dollars - effectively they reduced my available credit left to only a couple of hundred dollars 'available'. While it's they're right to decide how much they want to allow me to charge, the way they did it was just unconscionable. We were on vacation and I had assumed that I would be paying my hotel and other bills with the Amex card. This was now impossible. Luckily my emails are forwarded to my phone.
Fortunately (like most people and something Amex doesn't seem to realize) I had another card (not from Amex) and we were able to continue on and have a great vacation. Amex could have said - 'starting next month you can only charge this much' but they didn't. They just cut off you off with virtually no notice.
Now, they said my credit rating had changed. But I checked it that day. In fact my credit rating has improved over the last 2 years. Plus when you're talking to the customer service person they are really no help. They keep saying 'call the credit bureau' and the credit bureau keeps saying 'talk to Amex they made the decision'. Also, I have been an Amex card holder for over 10 years (although just recently 'upgraded' to the new Premier Reward Gold Card) and have never had a late payment, ever.
So, I will keep the card but for the next 2 years I will reduce my use of it by 75 - 80%. The only way I know of to penalize a financial company is to starve them of fees/revenue. I'm under no illusion that my small amount of revenue will change their behavior. But I thought I'd post my experience here for others to be aware of.
Bottom line - don't depend on Amex. Always have one of their competitors cards with you so you won't be left 'high and dry' when you are away from home. Instead of their motto being "don't leave home without us" it should be "don't count on us if you're overseas on vacation because we don't care"