Embarrassed customer

I’m am utterly disappointed/disgusted by the service I have received from the Checkers liquor shop , I bought 3 castle light 6packs on the 26/08/2020 I discovered a week after that 1 six pack is expired and expired on the 28/02/2020 . On the 20/08/2020 The gentleman man who assisted me told me to get the castle light that was inside the fridge hence they had stock that had already expired set aside ...so I did that without checking as I was told that the alcohol inside the fridge is new stock . Today the 3rd of September I went to checkers liquor shop to exchange the expired six pack upon arrival the security told me to go one of the cashiers Zinhle shozi she then escalated this matter to her supervisor micheal Mbele and he told me that this 6pack does not belong to them this utterly disturbed me because as old as I am I Would never bring an item that does not belong to them basically I felt like I’m a ***** or maybe taking chances , I asked him to check the footage or check the barcode of the item because it was scanned on the day of purchase . What Really puzzles me is that they did have old or old expired stock they could have made a mistake it can be a human error . So I left the expired 6pack case at the store as I was fuming because he refused to assist me in this regard and the staff were not helpful at all . I have taken pictures on the slip and the expired alcohol as proof . I’m sure you can get footage for the 26/08/2020 . This was such a disturbing experience it is very appalling that such caliber of people who checkers has nominated to head or run the store .