you have cut your ties, now run.... and dont look back. i would file a complaint with the BBB, and give the shop bad reviews on as many online sources as possible -bing, yelp, ect. yeah you paid way too much but live and learn right...? the guys is a joke and so is his shop.
yeah the TB(throttle body) cleaning is a part of the instal process for most places, but a couple of cans of TB or carb and choke cleaner and a wire brush will do the same thing, and those can be bought off the shelf at any auto parts store for under $20, $150 for a cleaning kit...?!? yeah i want what hes smoking. and cleaing that would only take like 5-10min, not a half hour.
as far as the computer goes, no. our computers will reset them selfs, just pull the EFI fuse or disconnect the battery for 15-20 min and its done. damage to the ECU(computer) on these trucks is pretty hard to do. they are not indestructible but it takes some trying to be a real idiot to damage one. just running the motor with a bad sensor or bad part isnt gonna do it.
as far as walking into the shop bays, yeah the guy kinda has a point there, its his ass if you get hurt out there, and his insurance wont wanta pay for it, it covers him, and his employes, but not patrons especially if not authorized to be out there. most shops will let the vehicle owner into the bay but they generally will escort them out to their vehicle to show them the issue, or let them retrieve personal items out of their vehicle. if its just talking to the tech that you want, they will typically call the tech into the office. with that being said, he didnt need to be a dick about that. next time, id just ask the next shop if it was ok for you to go out and take a look or watch. chances are they will say ok especially if its just something minor or basic, but its a courtesy thing.