Well, your 'dealer'/ bike shop owner is an idiot(s). I would suggest you do these jobs yourself. I never take my bikes to a bike shop as I do a better job and take care. You also need to pay attention to the bike a bit more.
"Idiot"... of course not, just people that want to be paid with the least effort they can get away with. It's also solvable, check their jobs asap, and picking it up at their shop, to do it there, is the best way to give them no blahblah out.
I started to do the latter with the dealer of my previous set (two) (singlespeed from beginning) bikes.
- A ball too much in rear wheel bearing causing pressure that forced cup and cone apart, resulting in alot play already when walking the bike at hand out of his shop.
- A longer tube for handlebar, to sit higher, came loose on the first road bump, less than a km to walk back to his shop.
- A "spacer" to get the chainline good, actually was some alu ring from wherever with 3 holes in it, discovered when it broke at the first pedal push when leaving his shop.
I had asked him in the shop to directly mount the rear wheel, so that I could check if the job was not botched, good I did, it was.
And So On.
See, it's a matter of checking the job of personell you hire already at declared "done" time. Since I started doing that, no surprises anymore when things assumed as ready spare turn out to be not ready, leaving one with in-use and spare(s) both out and need for a pick up.
Also, this way no excuse for extra billings, since the botched jobs are at the same time, in/near shop identified as such, which makes it impossible to blame it elsewhere.

See that ball too much in the bearing case. I was watching while he disassembled, he couldn't hide it so had to admit.
Regarding your claim that I wouldn't pay enough attention to the bike, that's baseless flaming out to lack of real arguments to come up with.
But that's no new story eh Mister fossyant? We read on...