If you did your research, did you ever think to bring a box, with heat packs for the ride home?
A hatchling that gets that cold/hot (bringing her out in 30 degree weather, waiting for the car to warm up, then the car heating up, then back out in the cold going into your house, then to a perfectly heated enclosure might have been too much for the snake to take.
A pre heated box (activate the heat packs when you get there, so its warm when you put the snake in)would have been a better idea.
just my $.02
Also shipping in cold weather is not a big deal, if done right, I know a boatload of breeders that ship every week of the year.