Speaking of paying an Amex card via MoneyGram, I've been having an issue paying off my Amex Everyday credit card.
I tried twice on different days to pay $1000 at a Walmart, but the system returned "invalid account number" every time. The employees even tried multiple times just to see if the card account number was typed in incorrectly.
Any advice? They've tried PAY ANY CREDIT CARD (1500) and AMEX STANDARD 2-3 DAY (14398) with no luck so far.