Sirileo, Wow, this ALL sucks, then another screw up. But . . .
The body shop didn't hook up the drive shaft that the tow truck driver removed? The body shop replaced the bed, which probably involved under-truck work, but at the opposite end of the truck (pic appears to be front drive shaft). And, that shaft was kind-of in its right place, unless somebody rolled up there and looked. They probably never had the truck on a lift, I wouldn't really blame them. Now, if the body shop did the suspension work, I'd be a bit more upset.
I'm a bit confused who disconnected it when. Your original post had a picture of the truck on a flat bed rig, in which case disconnecting the shaft wasn't necessary. So, I'm thinking maybe the tow truck that retrieved it from "down the hillside" had to use a cable to pull the truck out, did they remove it? In this case, it appears to be a part-time 4WD truck, otherwise that shaft would have been launched out from under the truck as soon as it was moved under power. That could have been disastrous.
Anyway, stuff happens. The TT driver might have removed both ends and put the shaft in the truck. Or leave a note on the steering wheel. At least he thought about removing it (Was it really necessary to disconnect it on this truck?). I just can't see blaming the body shop for something that wasn't their job.
HJ - The drive shaft(s) need to be removed when towing an all-wheel-drive or full-time four wheel drive vehicle with a standard hook/sling truck, or when flat-towing. Other vehicles might need the shaft removed if towing over a manufacturer-specified distance. All of this is to prevent transmission damage due to lack of lubrication. Most modern transmissions have only a front oil pump, years ago autos also had a rear pump, which would lube the tranny if the drive shaft is spinning. Your owners manual can tell you for your auto/truck. The best way to handle this is to use a flat bed tow truck.