Pick and Pay knowingly sold me me expired goods.

I went to PnP Something nice in Bluedowns to make a purchase, decide to buy some packets of chips, I bought couple of those including small packet of cheese curls ***** for my son. Next morning get told by my partner the cheese curls (which I bought for my son) are more than a month expired. I took the chips back to the store, upon entering the store, the manager was coming out of the office (behind the tills) I asked to have a word, his response was, "me?!" as he approached, I presented to him (while passing) the packet of chips and while I am talking telling him it is expired, he cut me saying "that is why they are marked to clear". I asked him, does that mean you have deliberately sold expired stuff? His response was, that is why it is marked to clear, there is more like that in the store (that time he is moving away). I immediately called PnP head office to confirm what he said, the lady said "no sir we only mark to clear stuff that is soon to expire not expired stuff", after purchasing bread I came back to him as he was next to the exit/entrance, I told him what the lady from the head office said and his response was, "check other PnPs". I requested his name as he did not have his name badge on, he asked why and I told him I will lodge a formal complaint as according to my knowledge the expired stock should not be on the shelves and his response was "my name is not available for this purpose".

I called PnP head office and lodged a complaint and the lady on the switchboard rep****, a lady by the name of (not sure I should write the name) will contact me, I asked the time frame so I may be able to follow up and the lady said "like I said to you said she will call you" and dropped the call. I received a call about 10 minutes later, the lady called me and I explained to her what happened she asked for my details and sai she will contact the store and get to back to me, I gave my details and waited and since then I never heard from PnP to this date. I called on Thursday (day before yesterday) to follow up and the lady on the switchboard told me the lady will call me but I did not receive the call.