Trouble adding FF# to rental
 

I use a corporate travel website for all business travel reservations. I often find that my DL Skymiles # has not been added to my Avis reservation. It has not been a problem adding it later at the Avis website, until last month. Now, I add the number and it appears to be accepted. But I go back a few days later and it is not there. I add it again but it doesn't seem to stick. I sent an email/feedback and was told by 'Nancy' that I should call customer service. Before I do, has anyone else had this problem and do you know the cause?

I've given up trying to get my FF # in my record for reservations made through corporate travel. If I remember, I give it when I return the car. The other times I just give up on it. Just another annoyance renting from Avis.

Edited to add:
I just noticed that Avis.com allows you to add the FF# to past rental agreements, now I'm waiting to see if they post. Finally a nice customer service item from Avis!