Ignorance and Neglence

I had 2 occasions with Shoprite in Boksburg Town CBD, I once bought few items and not everything was packed including meat , Once again last month I bought few items but unfortunately my Sour Cream and chocolate was not packed and all the time realised when I get home and it's too far for me to go and its costly, said thing is that there are packers there how do they manage not to give customers everything they paid for and with security guards at the door that check slips but cant see missing items that were paid for, my question is what are they actually checking and packing? I'm very upset with these incidents, Shoprite it's mostly convenient for us people who are unemployed yet they afford such mistakes.