Pep club card

I was denied access to purchase at pep Mondlo mall because i did not have pep club card. When i was about to pay the cashier asked for pep club card and i ddnt have, she them stated that she cnt assist me because i dnt have a card and i should borrow it. When i told her that i cnt borrow it she then said i cant buy without a card. I asked if its a must or optional to have a card. She said its a must and that was the first time hearing this since store points card are optional. Can the head office intevine in this matter since it is hard now for me to buy at pep