Shoprite protea gardens

So I went to purchase stuff from the 50% sale they had the past weekend some of the stuff I needed was not the I went to the cashier explaining and asking for rain cheque since I needed the products her then called a supervisor to come assist what annoyed me about its that the lady get to the till and says she can't assist rather she will call the manager and that why didn't I come beginning of the special what's that am disappointed in shoprite.