no idea what's been going on here between these two parties. No one does, and to write the exchanges here could be potentially libelous. What DINO has shown is NOT libelous in that he's showing images and kept it to facts (although the opening salvo was a bit murky). But be warned: if Nick were to lose a single customer based on this post DINO could find himself in some serious legal trouble...unless everything stated has been fact. That's the definition of libel.
My opinion based on the pics alone: DINOs frustration is warranted. 100k? And rust of any kind? Absolutely unacceptable. You can get a completely brand new steel body - primed, painted, and on the road for under 20k these days.
Conjecture: If the payments were slow (which DINO claims isn't the case) leading the truck to sit in the corner, then the correct response is to ship the truck back to the customer and say you cannot continue the work under the circumstances. It's a typical business practice and saves all this; I've had to do this before (not truck shop) and, while it's pissed off the customer to no end, no one else blamed me for shoddy work.
Nobody knows what happened here based on a handful of forum posts. The value of your post is simply the receipt of this feedback: yes, for 100k rust of any kind is unacceptable. Maybe it was the painter, maybe it was the shop, maybe it was the shipper, maybe it was that damn sasquatch...regardless, yes..you have a right to be frustrated.
..but what do you plan to do about it?