bad service/ bad attitude

on Thursday the 22st of October went to buy some groceries at Shoprite in dobsonville and i bought a box of Kellogg's and when i was making breakfast for the family Monday morning , the box was sealed and i opened it only to find out the inside pack was opened , so i decided to take back the box and get a sealed on because i need to look after my family health, waited five minutes to be assisted , security told me i can also speak to a lady who is in charge of the Cashiers spoke to her and she gave me an attitude first off all telling that i can buy something on Thursday and come to report it 5days later, she even suggested that i might have opened it myself and now am returning the pack, in her mind she thinking that am that broke that i open the pack and now i want a refund, she took the pack and went to about 3 people in the store telling them that look this lady is returning the box that she opened and now she wants a refund ,making a joke of my complain, she even said it's the first time she sees this and i told her the is a first time for everything, asked her , her name and she told me that her name is joys but on the floor everyone is calling her Grace.<br> please assist.<br>