Woolies Richards Bay Cashiers Food Refuse to let me swipe my MY SCHOOL Card

Ricahrds Bay branch cashiers at food are advising us to not swipe our My School cards when in store discounts are not applicable to items purchased. The more I tell them its for my Discovery Healthy food cash back the more they insist but you don't need to swipe because what you buying is not on special. Happened twice. Smacks of lazyness. I would like Discovery Health to comment as well as I have tagged them on Twitter. Woolies response by DM is I must look for the store manager and complain. Where does anyone have time for this??? I am complaining to you and you are referring me back to the store manager??