How can I stop the nuisance caused by neighbours hitting our windows with ball?

In our building, there is a play area that is all in glazed windows, all my windows overlook the playing field.

We have a sign that says you can’t play football and cricket, but everyone ignores playing football and randomly hit our windows. I’m always scared of fear, burned my hand 3 times when cooking and ironing.

The security guards asked them to take the balls, but the parents gave the children other balls, and so on every day.

The security guards were tired of asking and then they were completely ignored, I called the police myself, but they didn’t come more than once, but called once.

My son while doing lessons is also frightened by hitting the ball against glass. I asked the office of the security manager. It turns out no one will help.