Pick and pay overcharge quanity

Hi, I bought some items on 17 Sep 2018 from Mokopane Pick n Pay, from till cashier Simone Maseko. Two of the prices, was wrong. I waited more than 30 min for Helen to sort out the problem. Then I had to ask for about the double the difference policy, as Helen, who helped me, did not at first give it to me. Only after I told her about it, the double difference was given after another 10 minutes of waiting. After I came home, I double-checked the slip and was shocked to see that I was charged for 6 x PnP tuna chunks in water cans ( R19.99 each – Total R119.94) - on the slip, but I only bought 2, and there was only 2 in the bag. You can check the camera's on that till. I have the slip with me me. The details on the slip is as follows: * 669 ********** 872952 2 17.09.18 15:46 * s number ********** ********** 692078 This is not the first time that this happened at that specific Pick 'n Pay. We can't just go back, as we live in another town. Please advise me as what I am to do. i emailed pick and pay on there website with no reply to date