Dollar Tree

Yesterday I visited the Dollar Tree store and the cashier was so pleasant asking me how my day was. As we talked while she checked me out the manager Gina stormed up to the register interrupting her and proceeding to reprimand her for how the shelves looked. In front of me and the rest of the store she loudly spoke to the cashier as if she was her child. I was so embarrassed for the cashier and as she looked like tears were about to flow I told the manager that what she was doing was not only unprofessional but inappropriate. She replied pointing at my bag saying if I had a problem I could call a "Robert" but he wouldn't do anything about it. I am astonished by the behavior of a manager and I want to speak with the regional manager about her unprofessionalism.