My friend did this and her kids were around 7th and 8th grade. She left them home and gave them assignments to have done before she got back. They'd sleep all day, play games on the computer, they started chatting with "friends" they made online in the games, and more.
That's when she laid down the law. They got up every morning and went to work with her. They sat in an empty office and did school work all day.
They both finished high school a year and a half early. Because mom found out that kids are kids and won't stay on their work, they want to have a life and they'll find a way to have it.
I do think the solution to this issue is to find someone who is home all day and ask them if daughter can stay with them during the day.
Or if that person drives they can be available to help the girl if she needs it but then they can take her home when she's finished. Perhaps even some home school organization in their town can offer some assistance or they may know someone who is already doing this.