Discount not deducted

I have the Pick n Pay smart shopper App on my phone where I would usually go to download my personal discounts. Once I download this to my card and swipe at the till for that specific item that's discounted, the price changes accordingly.

In my experience on Monday afternoon the 6/5/2019, I had a R7.40 discount voucher on assorted Nestle nescafe cappucionos 10 pack. This was valid for 1 box, I bought a box at Pick n Pay family Springsgate and noticed after walking out of the shop that my discount didn't come off. I then thought I hadn't yet loaded the discounts to my card, after rechecking and making sure I had indeed loaded it correctly. This discount was due to expire 8/05. I made my way to Pick n Pay family Sherwood where I wanted to purchase a box of cappuccinos again and noticed that my discount has not been deducted. I called the till supervisor and she checked on my discounts on my smart shopper card on the computer in store and printed it for me. We tried to scan it again and again at the till and it would not reflect a discount. Her answer to me then was to report it to Pick n Pay as they can't do anything at store level. This has expired now and I am very unhappy that I wasn't able to get the discount that was allocated to me.

Please sort this out as I would not like the embarrassment at the till again for something that was a Pick n Pay error.