I bought some snails online at Salty Underground when I bought some expensive and probably now dead Berghia Nudibranchs. Astrea snails, and I was shocked that they are actually doing a good job. I should have bought more (I bought 20 and maybe 2-5 of them died).
Having said that ... they were shipped overnight FedEx and luckily, I have a Ring doorbell because the FedEx guy came to the door, put the package down SIDEWAYS, even though the box said "fragile, this side up" but luckily the bags weren't leaking into the cups they were shipped in... and he didn't ring the doorbell or anything. Had I not been anxiously awaiting their arrival, they would have frozen on the doorstep.
Salty Underground is good, FedEx is not (for this anyway).
V