Poor service

Yesterday my mom went to pick n pay Bramley and bought few things where she saw a special for 5 packets of biscuits charged at R55.00. She added those to her trolley and when at the till she was told they not on special. She asked how as there is the special sign at the aisle. The cashier asked her supervisor to assist and went to check out the special and the answer we got was this was yesterday's special. Which I understand the shop can have daily deals but why not remove those promo's the following day? This was at 17:00 already and we can't have a lousy excuse that it's busy. I believe that the employees come in few minutes or an hour before the store opens to set up for the day. I'm not saying we should get special treatment for this but a simple apology for this not the superior telling my mom she's not going to credit her for yesterday's special sorry. Can we treat customers with respect and acknowledge when we in the wrong as a store. Yes you had the day’s special but remove all irrelevant specials from the previous day