Dismal service at SPAR 2nd Avenue Verwoerd Park manager

Today I went to Spar 2nd Avenue, Verwoerd Park looking for the Omo washing powder that was on Special. I was there on Friday and the staff told me it will be there on Saturday. Saturday I went there again and the huge delivery truck just arrived. I went there early Sunday morning during a heavy rain and found nothing. Later the afternoon I returned to the store and asked a staff member who was courteous, professional and helpful. When he arrived with the 4 bags the white manager shouted him in front of the clients and me. The staff member was humble and respectful to the manager and tried to explain that i asked for it. The manager turned to me and told me, you will only take one. He never greeted or acknowledged me at all. I told him I will take four and showed him the adverti*****t that says maximum 5 Spar deals per product per customer. I advised him that the Consumer Act says a sign must be visibly displayed saying one per customer. He said i must not tell him about the law as he is not scared of the law. I advised him the law is there to protect and not scare and this is the 6th time I am there within the 3 days looking for it. He rudely took one bag and walked away saying I can take three. Is it because i am a person of colour that I was treated so badly and is it because the staff member that assisted me was also person of colour that he scolded him in front of everyone?