Pampers Special 2 packs for R219

my daughter rushed into the pick n pay store in chatsworth and purchased a pack of pampers she was unaware of the special which she had purchased with the special time frame until we saw the add on FB she had went to the store only be treated badly then i called the store the next day spoke to csd manager who came back to hours later only to tell me they can not do anything i then called the call centre spoke to the one of the agents they also told me that they can not do anything - my point is that upon payment at the till point the cashier was supposed to tell you abt the specials however she rushed in and out and i believe as a customer i should be treated fair i am not asking for a free pack i just want the special that was advertised as it was purchased during the time frame very disappointed they gave me a ref no ********** 604