Reward card policies changing without any notice

I am super irritated. I ran into pnp Gordon's bay today, my 2 little ones were asleep and I asked their older sister to just wait with them I will be quick. Sped through the shop to realise I had grabbed the wrong rewards card. And as per normal, which has never ever been a problem, I asked another customer if I could use her card as I had forgotten mine in the car. The cashier told me, I am not allowed to use someone else's card. Flabbergasted as to when this new rule started, I asked this lady, so I must go all the way to the car and then come back for a card, she said yes. Furious I ran to the car, when I got back the cashier proceeded to ring up 2 packets of nick naks too, I looked and she asked if it was mine, so already irritated I said no, then she asked me, and the kiwi shoe polish, I said no what kiwi shoe polish, as I did not even look at any polish!

Of pnp can spam my emails why can they not inform me of such stupid changes? Either way who would've lost anything just for someone to swipe their card?!!

Pathetic