They ghosted her or stood her up.

They tagged her in Instagram photos which she wasn't in. They would invite her to a restaurant, have her wait for so many minutes but then never show up and go off to the cinema and then show up later. Kimmy went to confront those mean girls and they fake apologized her into paying for their food. She walked away, but Stephanie was secretly spying on them behind some newspapers she was reading, a table over. She did her homework on those 4 girls. She exposed the leader of the group on how she mocked the other girls behind their back. At the beginning of this episode, Steph walked into the kitchen & said, "Did you know we had a dryer back there?" Back to the confrontation, Steph hinted that the head girl might have graduated with her, meaning she might be way too old to be in high school. Steph gave the skinny girl some fries which looked delicious. The head girl was afraid that Ramona would become more popular than her, but she smirked, "I have everything she (Ramona) has," Steph interjects, "Except a kind heart." As Steph walked away, the black waitress complimented Steph for standing up to the bullies, "Wow, I wish my mom would do business for me like that."