I just had the same thing happening to me last month.
Two years ago they lost some of my Halloween photos which were recovered within a couple of days. If I recall correctly it was three or maybe 4 days.
In November I did have a couple of Photopass cards and couldn't remember which card had the lost photos on. Took them almost 3 weeks, but they found them.
I had given up meanwhile and ordered my Photopass CD, and they were even so nice to send me a coupon code that allowed me to order a new CD including the lost shots for free.