Did you check the superworms before taking them home? Some pet stores have the superworms around for a really long time before they sell. I always open the container and count to make sure it contains an approximate number of live supers. I've opened containers that have no live ones. If you still have your sales receipt, take back the container and show it to a manager. They should replace it for you, but check the new container. Whatever you do, don't put them in the fridge. Unlike mealworms, they will die in the fridge.
Aliza