Other Car Rental Programs/Partners (ie. Alamo, Enterprise, Sixt) - Alamo Says No Miles

Sent an inquiry to Alamo because miles didn't post to AAdvantage.

Response: Thank you for taking the time to write us regarding your frequent flyer miles. Please allow me a moment to explain. Some companies decided to disallow accumulation of frequent flyer miles when renting under their corporate contract. Your rentals were under the corporate contract for American Express which disallows mileage.

So is this Alamo saying no miles, or Amex saying no miles?

Sent an inquiry to Alamo because miles didn't post to AAdvantage.

Response: Thank you for taking the time to write us regarding your frequent flyer miles. Please allow me a moment to explain. Some companies decided to disallow accumulation of frequent flyer miles when renting under their corporate contract. Your rentals were under the corporate contract for American Express which disallows mileage.

So is this Alamo saying no miles, or Amex saying no miles?

AM EX has cut you off.
There is a fee that is charged to the rental car companies to credit your miles and part of that is charged back to the one who is getting the credit for the mileage program. Since it's a corp rental, AM EX is reimbursing for the rental and doesn't want to pay for the FF charge...so isn't allowing you to get credit for your mileage program.
You aren't the only one. We have several Corporate Rate partners that won't allow their employees to get mlg credit from us anymore...because they don't want to pay the fees.
Now you might try Back-dooring the process.
Call American, tell them you rented from Alamo, give them your Rental Agreement number and the dates you rented and see if THEY will credit you directly. I have no idea if this will work but it's worth a Try.