It's taken over a month, they don't have anything even wired yet, and no finish work even started?
I'd walk in, hand them a bill for the rental, compare it to the cost of the gear and the "working time" on your truck, and walk out, with keys in hand to your truck, and drive that ***** away.
A buddy of mine has a CNC machine, he could have done all that intricate scroll work in about 6 hours of shop time (including the CAD designing). To put that shit together, I'd be able to do that in about 3 hrs.
My enclosure in my rear quarter panel had to have every piece scribed to fit tight, trimmed, scribed again, trimmed, etc... and I had it done in under 6 hrs. I spent another 5 hours running my 1/0 wire along the framerail, up through the floor, mounting my distribution blocks and amps, wiring everything up, connecting the RCA's to my JVC head unit, and programming the Steering Wheel adapter to work. Even though I did work in a shop 25 years ago, I'm no "pro".