The group of girls chased year 9 student Addison Rice, her two sisters and her mother through Mount Barker Central, after following her from Mount Barker High School.
Addison and her family were chased into a Specsavers, where staff helped them by closing and locking the front door, keeping them safe inside.
Addison’s father Paul Rice said the experience was distressing for his wife and children.
“[They] started yelling screaming, [they were] abusing her, threatening her, trying to punch her,” he said.
“One of [my] other daughters had to step in to stop these [girls] from attacking [my] younger daughter.
“I had my wife and three daughters in that shop being protected by the people that work there.”
Read Related Also: Take That to perform at Prince Charles’ coronation concert but key member will be missing
Witnesses said the group ganged up on the girl, and left some older customers feeling unsafe.
Rice and his wife want the Department for Education to step in, as well as the police.
Officers dispersed the group of girls at the scene but said they would not be taking further action.
Mount Barker High School vowed to take “strong action once the full details of the incident are determined”, in a letter sent out to the parents of enrolled students.
Parents are calling for harsher, potentially legal consequences for intense bullying incidents.