False advertising or not - E voucher

Pick n Pay Wellington is advertising this week if you can that barcode, you can get a R75 voucher to use. Done that, got a voucher code. When I got to the till today the voucher did not work. There is R0 on the voucher. The front house supervisor just pulled back her shoulders and said there is nothing they can do. Now was this false advertising so that Pick n Pay can reach more people through whatsapp? Shocking Pick n Pay. Now my reasoning is, my daughter also tried and she got a message that they reached th 10000. Which is fine. But my issue is if I got the voucher code then surely it must work. No Pick n Pay, do better. And Pick n Pay Wellington your staff's attitude stinks.