Did they come in with a sunken belly? Are they eating normally already??
I got stuff from blue zoo aquatics a couple of times and they are well shipped, I trust them so far. The stress guard sample is awesome.
I have never used the vendor you had issues with, but on the flip side : could part of the delay be due to the holiday weekend?? As a customer it sucks either way, I get it.
As far as mine from Blue Zoo go, one is actively seeking out food, the other is still adjusting and only catching scraps as they come her way. I don't think either looks sunken in at all, but I do feel they look a little underweight still personally.