Bargain Deals

Company displayed a promotion on board...When I took the items for payment the manager told me its not on promo with an attitude after scanning and that was when they tried to look for a loop hole by looking at the small print which stated items were on offer till 05 April and that was she even removed the display and called one of her staff members to remove the promo! I would like to know whose responsible to ensure that displays are changed in time? Customer or the floor manager??? So strange in this case that the manager herself lacked knowledge about her own store and to top it off she had an attitude and acted like my money meant nothin when she returned it....