Expired food

I bought OX kidney from Shoprite in Sunnyside at Esselen street in Pretoria. As I was cooking there was a bad smell and the date "sell by 29.05.2019" and I bought them on the 27th of May 2019. Someone is not doing his/job by checking the food if it's healthy or not(rotten). Checking food if it's expired should be a priority as we can easily get sick and chances are that after we can require madical attention. Do your job!!!