Seeking advice

I currently work at this company where they dispatch teachers to nursery schools.

Other than regular lessons, one of the jobs is to do kagai to teach up to 10 kids in the afternoon solo in a free space at a nursery school where they do workbook, games etc, 2 x 40mins each.

I have no other coworker or Japanese teacher supporting me. I have to handle everything myself (running the lesson, keeping kids calm in English, communicating with the parents)

But I worry about kids fighting, hitting each other and causing injuries or even running around in the room, I worry about the safety of the kids under my care.

I can't call a nearby teacher without leaving the kids in the room by themselves if I have problems.

I reported an incident that happened during class to a nursery teacher after the lesson then the company tells me not to tell them directly but to tell the office.

I asked for another teacher to support me, they did schedule some for a while but stopped as it's not supposed to be team teaching.

The result was better with a supporting teacher and I was able to teach comfortably.

I am sorry if I'm not clear.

Is this normal? Is this legal? What should I do?

Thank you in advance.