I'm not the other guy, but I call bullshit as well.

I've been in retail, from the lowest shitwork to manager, since 1987. I've had dozens of confrontations, over little things, and big things. If I've heard the person out, and done my best to make the situation right, and they still won't leave, I give them a few chances / warnings, and then I call the police. They are interfering with me doing my job. I've only had to do this maybe twice, actually calling the police. I've never had an encounter last more than about 20 minutes.

Maybe it's the price of the sandwich changed and she wanted it changed back. Maybe he offered her the money and she wouldn't take it on principal. Maybe she's just a psycho who wouldn't leave until she'd had her fill. Crazy has no concept of time.

If you can't make her happy, and she won't leave, what are you gonna do? Are you literally going to let her argue at you for two fucking hours? No you are not.