Dealing with disruptive students (that I don’t teach)

I teach once a week on Saturday at a small eikaiwa. The owner / manager is rarely there, and when she is at the eikaiwa, she's completely checked out.

We have a two disruptive students (three years old and ten years old) from the same family on Saturday and I'm basically at my wits end due to how checked out our owner is. The moment they come in (usually an hour before classes start) they immediately come into the office and take toys off from the shelf. They're not my students, and I'm not there when they start playing freely.

How would you deal with this when students playing around end up disrupting other classes?

by ChickenPaul3745