Checkers deceive their client through their app

I am very disappointed with Checkers. I checked a product on their app, a J&B 200ml and it shows its selling for R30. I went to the store to but 20 of these as I am preparing for my son's celebration. I get to the store and its selling for R64. When I queried this and showed them the price on their app, they tell me that the packaging has changed and that the one on the app was selling at that price when they were phasing it out, which was a long time ago. My complaint is that they are deceiving their clients with false advertising because if the price is no longer valid it should not be on their app. They only offered to sell me only 3 out of the 20 I drove all the way to buy. The branch manager even downloaded the app to check if I am not lying and he also saw that R30 is the price on the app. Checkers is deceiving customers and I am not happy what so ever with them. I waited in the store for over an hour just to get them sticking to their ********* ways. Why have an app if you are going to give your client false advertising.