Bad Attitude

I was at shoprite on the 19/01/2019to buy a washing powder.as I get to the till the cashier was serving two ladies and they were leaving.she said to me she is closed but there was no close sign.i told her where is the sign so she took from the front and put and say there it is,you like to be treated special and you are not special.i ask for manager and she called a supervisor who took my one item and ring it bcos she refused to serve me and stood up shouting at me..that was not enough I demanded a manager and they pointed me a lady in the office.i went to her and she was a trainee manager she listen to me and the cashier came in the office and keep on saying u wrong u wrong until the lady asked he to shut up..is this shoprite customer service..that cashier is rude..