Maggots on food purchased

I went to Spar Palms on Corner North rand road and 1st street Boksburg on the 16 Jan 2019 Bought a pizza and when i got home i looked closed and there was full maggots on the pizza All Spar could say was that i could return the pizza.Who sells expired food and who is doing quality checks..... This was so disgusting ......do they also think people have money to ride up and down...