PICK N PAY misadvertising

Did some shopping there and saw a special advertised on the shelf . It says ANY 4 for 95 rand . So took 4 packs of washing powder but at the till point got told to see the manager . Went to see him and was told that it's a printing error and to take it up with head office . SO WHY DO THEY THEN PUT THE AD UP IF ITS A PRINTING ERROR ! Price displayed on the shelf is the price to be paid . This was not the first time as I previously bought items there BUT when I get to pay and they scan the price is always a rand or more than displayed This is pure dishonest ******* on pick n pay witpoortjie behalf . They are rude and incesitive and the management should get some training in public relations