Re: How to get the npc maid to work
Yeah, what @JonaO703 said. Sadly, maids are kind of buggy, IMHO, although it's been a while since I had one so maybe they've gotten better?
Basically, in my experience they only clean up "a mess." So they would come in, sweep up my Crazy Cat Sim's pet hair piles on the floor, wash the dirty dishes on the counter, take out the trash, and say "Looks like I'm all done here! that'll be $X." If you lock the door and forget to unlock it to employees, they show up and charge you.
There's a bug report that maids are OBSESSED with cleaning the perfectly clean grill outside, sometimes to the exclusion of other cleaning. https://answers.ea.com/t5/Bug-Reports/OPEN-Maid-caught-in-a-loop-cleaning-grill-even-on-new-grill-Neat/m-p/10209362#M178484
And yes, as @JonaO703 pointed out, they apparently don't vacuum or dust. I can't test this, either, because I don't have it either, but that thread is linked above. (https://answers.ea.com/t5/Bug-Reports/OPEN-BDK-Maid-doesn-t-clean-dust/m-p/10226363#M178938)
(I used to have maids in every save, but I fired all of them after an issue where the maid decided he lived at my Sim's house now and refused to leave and just kind of chilled on the sofa eating all their leftovers, and there was no option to ask him to leave...)