WHAT IS GOING ON AMAZON WAREHOUSES?

I work on HR phone line and I dont really understand how warehouses work. Why nobody is able to reach their managers? And why is everybody always scare to got with HR on site?

I have heard terrible things in some calls and want to know it is always like that?

Sometimes i feel really useless over the phone for not understanding the enviroment, but iam from a different country and i guess our training is deficient...