I ordered a few serials from DD several weeks ago, of which almost all were reported as out of stock when ordered. Little by little they have started showing up in my mail box. I generally do not receive any notices from DD when an item ships. As a result, I have to check the website periodically myself for a status update. Also, while media mail seemed to go through fairly quickly during the sale, these are defintely taking the 5 to 10 business days to get to me.
I like to get the lowest price which is why I use DD on occasion but I've learned not to expect a speedy delivery. Best to forget about it and be surprised when it shows up. After many years of using them I've only had one occasion where an ordered was cancelled on their part because an item could not be obtained.