Shelf price

Went to the kliptown branch so I saw the 5kg chicken on promotion for 169.99 but when I went to the till it scanned 189. 99 the cashier gave me attude and told me it's not the item on prom and told 1 of his colleagues in vanic that we put the price there the Ram was also not helpful said they can't give it for that price they can gve us the 4kg