Re: Package started out poorly - now decimated
Sounds a bit like poison to me also. If so it does not necessarily have to be sprayed right onto your bees, there could be flowering plants somewhere else being sprayed.
There was a case where I am, of an ignorant person didn't like bees flying in their yard, so intentionally put out poisoned honey to kill them. That's pretty extreme probably not the case for you, but there are many ways bees can be poisoned.
Your 50 bees are not going to survive. But poisoning events tend to be seasonal, if you can find some more bees in say, a months time, could be worth trying again.
It's also possible that the bees arrived infected with something, without passing judgement because that is not possible without knowing, my advice would be try to get the next bees from a different source, just as a precaution.
"Every viewpoint, is a view from a point." - Solomon Parker