I think there's a TPA call center too. Either way, basic stuff like adding a mileage number is no biggie with U.S.-based agents.

I've had to do the reverse for my CO number on DL, and not only was it a pain, getting Elite seats was also a challenge.

btw, CO's website will let you add your FF number yourself. Just pull up the record and update traveller information, and add it there. They accept all partners, so no need to call. ^