Springtails in the winter

So I'm new to this hobby and wanted to start with plants only in a relatively small setup to get a feel for whether I have what it takes to take care of a terarrium/viv/whatever. While looking for plants online, I figured it would be a good idea to also include isopods and/or springtails and feed them rotted vegetables or something, just to have more activity in the tank and possibly to use them as a cleanup crew in the future if I ever moved on to keeping live critters.

So I ordered some of both after someone told me that you can get pretty much anything for this hobby online, and in both cases, all the springtails and isopods arrived dead! I'm now realizing that they often don't survive shipping during the winter, which sucks.

Do any of you order live critters online during the winter months, or is it best to wait until summer? Local pet stores don't keep small arthropods on hand regularly, do they? Should I just stick to the plants for a few months?