I'd tell her the fool at the store was so busy shooting himself in the foot and refusing female customers, we ought to open a store across the street from the idiot and let the free market solve the problem.
Of course, in your world, we'd probably have to wait a year or two and pay a bunch of thieves money for "permits" and bullshit like that, IF, we were "allowed" to even open a business there.
I wouldn't ask my mom to give me her pistol so I could go force the person to serve her though. That would be an act of offensive force, and would ...hey wait a minute...didn't I tell you to make me a sandwich?