Ver dissapointed Pick n Pay client

On the 15/5/2018 I visited the Pick n Pay store in Ruimsig, they had Kellogs on special for R39.99 for a 1 KG. I looked at the price and took a packet, when I got to the till to pay the price was R68.99. I advised the cashier that the price is incorrect and that it is on special for R39.99. The cashier (temporary Cashier 8) advised the supervisor. I explained to the supervisor what happened and we went to the isle where the kellogs was on special. She said that it is the 1kg that is on special and not the 1.2kg. At that point the special price was where the 1.2kg packets were. She moved it to the other side and said that they are all out of stock. She went to the till and voided the item. I advised her that I would like to see the manager. The manager (a African gentleman) came to assist me. I went to the isle with him and explained what happened to him. He said that unfortunately they can't help it if shoppers move items around on the shelves and he can't give the kellogs to me for R39.99 I would like to know how can he do that, don't you pay what you see? I am very disappointed by the way I was treated, by both the manager and the supervisor, they made me feel like it was my fault.