Bornes
Robot Giny
That really blows.
Personally, I would be worried about giving them an ultimatum. And my only worry would be how long they would try to string you along. They're obviously not upfront with their employees, and they also obviously don't really know what they're doing. So if you try and ask for a pay raise or threaten to quit, they will probably try to string you along for as long as they can, "promising" your pay raise in the next paycheck, but then oops, looks like there was a clerical error in the payroll department, I guess you'll have to wait two more weeks, blah blah blah until you finally just burn the place down.
If she's worried about that, then reword the letter.
"If I do not receive a pay raise and reduced hours, effective by [date], then I will no longer be working at [place] as of [2 week date]." Simple.
She loses nothing in putting down whatever the hell she wants since her objective is to quit anyway. If they follow her demands then she just scored a better job with little to no effort on her part.
But OP's made it pretty clear here that she doesn't care about a two week's notice, apparently.
You've had bad jobs before, haven't you?
So she writes the letter and gives it to her boss. He looks at it, and then says, "Look, Ghosty Pie. I totally understand where you're coming from, and if it was up to me I'd be paying you twice as much! You're one of our best employees! [Insert more compliments here.] But you know how it is with corporate, I have to go through all the red tape." Sympathetic smile and chuckle begin here. "Can you stick with me just a little while longer? This place would fall apart without you!" And more compliments and begging until poor Ghosty Pie finds herself agreeing to stay for at least another month.
Bad bosses are like slumlords. They're really good at talking fast and convincing people that what the person wants is going to get done, they promise and cross their heart and hope to die, but corporate has this policy and BLAH BLAH BLAH.
Yeah, you figure it out eventually that your boss was never going to give you a pay raise, or that your slumlord apartment manager never intended on fixing the broken dryer in the laundry room. But by that point you've wasted at least a couple of weeks, and sometimes a couple of months, hoping that this would get dealt with. That's why it's better sometimes to just take your losses and run.