As soon as I called them back after they left me a message with a reference number, the rep. Wanted my full SS# which I told them I wasn't giving it to them. They then asked for my full AMEX Card # to verify the account. When I asked what this was regarding they couldn't answer that until they verified the account. I told them I had a reference # from them; when I issued that number they couldn't "find me" so they asked again for my full SS#. I hung up at that point.
Fake AmEx debt collector! I was almost fooled! But as soon as they asked for my SS#, I knew!
They did have the last 4 digits of the AmEx card number. And when I called back it said "Thank you for calling American Express. This call may be monitored or recorded. To speak to a representative, please press 1 now."
Apparently looking for a payment
Called on the 13th, Payment was due on the 18th (but was paid and acknowledged by email from American express on the 11th).