Embarrassment and Bad customer service

On Sunday 13th May 2018, I purchased a gift card online because I misplaced my woolies card. The gift card was delivered on Monday evening. I went to Plattekloof Woolworths Foods store at just after 7pm. We bought quite a number of essential items for our kids school lunch as well as foodstuff for the rest of the week for our household. When we got to the till after the items were rung up we were told that the gift card was not active. A supervisor was called to check the card and she also confirmed that it was inactive. The staff gave the card back to us without offering to find out why the card was inactive. Myself and my family had to leave all our groceries that we needed and also leave with a red face as it was a very humiliating experience. There were no warnings or rules that were attached to the gift cards that said that it will only be active at a certain time. I purchased it thinking that I will be able to use it immediately. I have always enjoyed shopping at Woolies, but this really makes me skeptical of keeping Woolies as my preferred place to shop.