a lady shouted at me for opening blinds to check t

I went to buy blinds at irene Mr price home,i called a lady on the floor and asked if I can open it and check he size if it will fit my window and she said yes so I opened it and check and it was small so I took the bigger one then a manager came from the office shouting at me on why I opened it I told her that a lady who works there gave me permission to open it,then she said no that lady is a casual next time I should ask for a manager if I want to open anything I told her to stop shouting at me and stop with the bad attitude,she continued shouting telling me I can do what I want she even said I can call their head office she doesn't care.Is this the way the managers at Mr price home treat their customers? I have been in management since 2006 and have never been rude to my customers,customers pays your salary and a bad attitude will make them loose business she is dragging the companies name to the mud if has this attitude then she doesn't belong in retail what a rude lady!!