If one does go to Congressional, find a senior staff there like Chris or one that has been there for years. We have bought fish there. We do our homework and choose stock or equipment carefully there or any store. They have helped me with lights. One had an manufacturing issue. They ordered another one and when it was in, they called, I came in, and it was replaced.
With dead fish, I see that issue in other stores too. With LLE, IMHO there are a number of factors involved such as the food pickiness of that fish, any food competition, the health of it to name a few other factors beside the store. We all want good husbandry practiced.
If nothing else stop in and go compare with other stores. Perhaps one time WAMAS folk could do a day long aquarium shop hop!