Rotten meat

We visit our children from Ellisras. We go to Carnival Mall and biught some pork tjops. We go home and want to braai the porktjops but it was rotten. They kept our slip cause they advertise a special and when we want to pay it was R200 more so they reverse the transaction and kept the slip. My daughter go back with the rotten meat and the refuse to pay her or change the meat