Shoprite liquor Mabopane Square Bad service

I am soo angry Yesterday night I went to Shoprite liquor Mabopane Square, Got there @ 19: 45 where as it closes at 20:00, So I took my Six pack and paid at 19:53 as I was about to leave the Store I saw a poster of a special for the same brand I bought so I went back to the till to exchange that and buy the special one and that cashier by the Name of Brenda Kgaphola the very same lady that helped me not even a minute ago told it That it's Late she can't change for me, she wants to go home.... She Repeated her statement and said she won't help me and I should leave, while the Manager was there watching her... I am so Hurt and disappointed at the level of service I got..