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?