Trust me, I've had the same problems! I'm not entirely sure if it had to do with the store though, because your fish may have just eaten the shrimp. I once had 40-50 Cherry Shrimp and 30 Associated Shrimp; yellow, blue, orange, green, ghost, etc. They were in a thirty gallon that had been up for about two months with only four guppies, 6 neon tetras, and three albino cory catfish I had rescued (Couldn't get more) anyways, half the shrimp were gone the next day, and by the end of the week all that was left were a bunch of shredded pieces at the bottom and some fat fish. It was pretty traumatic and I now have shrimp in a separate tank, although I have struggled even with that. Personally, I just find shrimp really hard to keep.

 

Ya, the shrimp weren’t in with other fish, except the 2 cherry shrimp that survived. I still havent seen them since. I have noticed shrimp are hard to keep. any changes and they aren’t happy

 

I noticed that they recently started selling shrimp as well. I'm not surprised they didn't do well for you. Sorry to say.
🙏 😣