I've had damage to shipped vivs twice. One was a 40 breeder glass viv that the seller assured me he could ship safely. He did not pack it well enough the first time. The second time he got it right. At his cost.
The first time was a horrible experience. I ordered custom cages from a "company," (Jungle Plastics) a guy I guess who made them himself, upon recommendation from a member here. When they arrived, parts were missing, broken, corners were bashed in, they were dirty...I sent them back, at his cost, and he rebuilt them and replaced them, and had them packed professionally for shipping the second time around, and they made it safely.
So it's up to the seller to replace, and file a claim with the shipper if there's a valid reason. Usually, though, items just aren't packed correctly.
Good thing we are supposed to be certified to ship snakes, or the same thing would happen to them more often. You think that styrofoam is in the box for insulation but it is actually there to make the box crush-proof, and when you are getting certified and send in your test package, that's one thing they do is try to crush it.