false price advertised

i went to pick n pay senaoane to buy tin food for my dog on the shelf it was R13.99 then i took two tins when i get to the till they scanned R21.99 when i told the cashier that the shelf price is R13.99 she called the supervisor who went to the shelf came with the same price that i saw and another price then i said to the supervisor by the name of sibonelo lets go back to where i saw the price, we went, to my surprise there was still another price of R13.99 then when i show her were i took the tin food she said the price is written no name i said how will i know cause the price i see is on the same tin food that i took She said she is going to call her manager, then the manager came by the name of Lenard who said they are guided buy the name not the price i asked him but the price i saw it doesnt count he said no. The worst part where i saw the tin food, the was not even a single food that they say it was R13.99 it was only the ones that i wanted to buy