Expired items on shelves and overcharged for items

What ****ty service from pick n pay Westwood, Sherwood, Durban. I went to buy C***** Nolac milk on Friday and to get home after using the milk to see it’s expired. The milk expired in October 2020. I return take my cash back and proceed to do a lil shopping (I was very hesitant) and look on the shelves all their Nolac milk is expired and all which expired in October and December 2020. I called the manager and they changed it, so I took 3 of the items all which will expire in April to get to the check out and look at my receipt when I get home to my surprise the cashier charges me for 4x Nolac milk. What goes on tho ? Does it really mean that we now have to double and triple check everything??? This is terrible.