Please tell us how you set up your bin. Did you rinse/wash the trays before setting up? How much time before you added the worms. What kind of bedding, how much, how wet. How much food, how often? Did you add some food when setting up the bin? Where do you keep your bin? Not in the sun I hope. What is the day temperature where you live?

The first time around, how much time until you notice that they are dying? Little by little or all at once en masse? Were the carcass scattered throughout the bin or clumped together or along the wall of the bin?

How did the 2nd time happen? How much longer until you noticed anything, same way? What/How was the condition of the worms when you received and opened the package? Any idea how lomng they were in transit? I hope they were not left in the mail box or somewhere in the sun until you retrieved the package. What month was the 1st batch delivered and when the 2nd batch. Any idea what temp. was inside the bin?

Sorry for so many questions but none of us can tell you what you did wrong or if you even did anything wrong, if we don't know what happened. I assume you bought EFs.