B.C.
You need to understand how addiction works.
They have a dependency and their body craves the addictive substance to function - it provides the body with what they need to relax them, make them feel good.
Getting use to doing without that addictive substance is like having a constant itch on your nerves that you can't scratch.
Eventually that dependence will go away and they will feel better.
But until then they are going though heck and they don't have a lot of patience.
Just cut her some slack and encourage her - tell her you think she's doing a wonderful thing and she'll eventually feel so much better.
She's using arguing to try to distract her from feeling miserable.
You can just not engage in any arguing.
If she says anything to pick a fight - you just say 'Ok' and let it go.
Don't take any argumentative thing she says personally - it's the addiction talking and you don't care about anything it has to say.