item wrongly priced

Very dissapointed about the service I received at Protea Gardens I am launching this complain cos it's not the first time I receive such pathetic service from this brach their items are always wrong price today I bought a cooler box that was marked R109.99 when I got to the till point it scanned R139.99 the cashier called the supervisor when she got there she literally asked me if I can not read can I not see that I have the wrong price it's not for the item I had I told them the price on their shelve was wrongly marked they all told me to either leave the item or pay because I am illiterate I can't read they basically told me