Sheetstreet false advertising

So on the 2nd April. I went took my mom to sheetstreet. They have a special \Buy any 4 cushions and get 20% discount\". <br> We get to the till, Sinzo scans the cushions. The system doesn't show the discount so she calls her supervisor. <br> After a little bit of talking they tell me, oh, the discount only pertains to 1 cushion and not all 4.<br> <br> Which means that although the ad says \"buy any 4 cushions and get 20% discount\" we will only receive discount on 1 cushion.<br> <br> This is false advertising. I am sending a complaint to the Consumer Complaints department."