Sold rotten fish

Was sold rotten fish today at checkers with a sell by date of the 26th of December 2015 .So disgusting and filthy of a store in such a highly regarded place.I am not even able to eat anything after the bite I had of that fish and now have a stomach bug.Very disgusting indeed, when I returned it the lady was even shocked, because as soon as I opened the packet she could smell the horrible scent ..yuck.I thought my taste butts were off , but after my colleges shared the smell they could tell it was rotten fish,I mean how could you do that .