Wrong price advertised on display

I made purchase yesterday at mr price cellular store at cape gate. The iPods was R299.99 on display that’s what I saw was attached due to the affordability and saw what I like(iPods) on display. Went to make purchase at the till point next thing I must pay R399.99 but it’s R299.99 on display yebana. I told the guy I saw the items for R299.99 and you also can see there is a R299.99 price you guys packed it and no else. He said he can’t give me for the R299.99 price I kept quite and made purchase as I didn’t want to lose the iPods. I work for a retail store if us retailer store places items under the wrong price we are responsible and must give customer what they see. I hate complaining I was procrastinating yesterday about this review but had to do it as I was not satisfied about this.