Thats odd even though certain daily casualties are expected when dealing with livestocks.
LFS should have made a round to remove all the deads and check to see if any problems and make a note to staff not to sell livestock w/ problem, this all should be done prior to opening. This way they can build their reputation because word to mouth is best and free advertisement, I would think.
No matter how well I take care of my fish (from breeding) but depending on who buys, there are chance of fish not making on the other end when same batch on my end is experiencing no problems at all. Whose fault is it? Difficult to answer!
Anyway, hope yu have better luck w/ new vendor and try to get to know the staff who can honestly assist in your interest which in return will be stores benefit in long run.