I ordered Costco gc $100 online on Thanksgiving, but until today I haven't received any confirmation from AMEX that I'll get $25 back... is it something I should worry about?
Yes. I got an email from Amex right after I placed an order at Costco.com.
Subject: Thank You for using your enrolled Card!
Thank you for using your enrolled American Express® Card ending in
XXXX at Costco.com!
I've since received the $25 credit on my account as well.