It's usual with Zavvi website when release date arrives and not yet in stock the release date vanishes
When not sold out it also auto goes listed as sold out on their system on release date if no stock on system yet
You will see the same for Kong Skull Island listing on zavvi website
It's listed as sold out but it's not
If stock arrives this week Zavvi will charge debit/credit cards or list a new release date in a few days time
If stock arrives this week for example for Kong Skull Island listing it will change to Buy Now or back to Pre Order if release date changed
Zavvi usually update website 1-2 days later after original release date to new release date if it's changing.
Sometimes they have a delay in stock arriving and warehouse only get delivery on Monday or Tuesday