A few days after her trip to the city, Grimm said, she emailed some paperwork about the students to the school to ask when she would be getting paid the $1,800 or so that she was owed.
The school's principal, Sue Stiver, wrote back, and shared some astonishing news: John Craig, Frontier's founder and CEO, laid off the entire teaching staff March 9, after months of paying the teachers half their salary amid numerous financial and academic woes that were uncovered last month by the Daily News.
The school year came to a sudden halt. Grimm, her fellow educators and Frontier's 85 students were left twisting in the wind, like tattered plastic bags caught on the edge of a tree branch.
Parents of Frontier students have told the People's Paper that their kids have been sitting around for the last month, fretting about the classes they've missed, while Craig has offered little or no insight on how they'll make up the lost work.
Grimm, 55, said that she has sent numerous emails to Craig, asking about her back pay. She's never received an answer.
Craig did not respond to a request for comment.
"I have another three months of chemo coming up," Grimm said. "I'm single and self-employed, and trying to make ends meet."
The money that the school owes her "is not a little, piddly thing that I'd like to let go," Grimm added. "Not with all of the medical expenses that go with this."
The state Department of Education, which holds the school's charter, launched an investigation into Frontier last month.
Tim Eller, the department's spokesman, said Thursday that the cyber school has caused the investigation to drag by providing incomplete or delayed responses to information requests.
"The department is concerned about Frontier's willingness or ability to cooperate with the department and to comply with the school's legal responsibility to provide information and records to the department," Eller said.
He added that the department would take action against the school based on information it has received, or on the school's unwillingness to cooperate.
This much is clear: The situation has already dragged on far too long.
Grimm, who has been a teacher for more than 30 years, said that she found out about Frontier through the Department of Education's website.
The school, which opened in the fall, sounded like a dream on paper. It promised to offer students a world-class education, including art, music, foreign languages and career skills.
Parents and former staffers have told the Daily News that those programs were eliminated as the year progressed.
When Craig, an associate pastor at the Philadelphia Revival Temple Church, successfully pitched the school to the state, he said that it would have about 300 students in its first year.
Frontier attracted only about 85 students, including 54 from Philadelphia. The Philadelphia School District is providing Frontier with $435,520 to educate those students.
Craig said in a previous interview that the students were performing fine academically, but records viewed by the Daily News showed that numerous students were failing or habitually truant.
Grimm said that after she was hired by the school she evaluated three students for possible learning disabilities, including two from Philadelphia who clearly needed special-education services.
In a normal situation, Grimm said, she completes a report and sends it to the school so that teachers can add their input. The school is supposed to then contact parents.
"But who's going to follow up at this school?" Grimm said. "There aren't any teachers!"
Nancy Campbell, the secretary to the school's board of trustees, said in an email that Frontier was on spring break this week but is otherwise "up and running."
"Any and all academic concerns, should they arise, will be addressed by our administrative and instructional staff," she wrote, adding that Grimm's issue is being handled by the school's attorney.
Another parent, Angie Stone, of Hanover, York County, said that she's been hounding the school and the state over the lack of teachers and answers ever since the staff was laid off.
Her daughters Carey, 18, Rachel, 15, and Harmony, 14, are all Frontier students.
Earlier this week, Stone said, she was contacted by two teachers who said that they had just been hired by Frontier and were going to start working with her daughters. She hasn't heard back since.
"I need a resolution for my kids," Stone said. "The whole system is kind of screwed up. Where is the accountability?"
Contact David Gambacorta at 215-854-5994 or firstname.lastname@example.org, or follow on Twitter @dgambacorta.