Expired goods popcorn

I had the worse experience in spar gateway on the 16/10/20, i went to grap something to eat and some popcorn for myself and i looove popcorn i eat it daily, i bought the hoppity poppity brand the cheddar cheese flavor, paid and i was gone got to work ate my food then after i started nibbling on my popcorn but the taste was horrible and i didn't think of anything i tot it my mouth as i had just finish eating stood up went and drank some water came back continued to eat no it still tasted bad i took the packets close to my nose i smelled it, it had a funny smell and it was stail as i asked someone else to taste it mybe my taste buds were just tricking me, and i checked the expiry date to my surprise the popcorn had expired 4 months ago expiry date was the 7/6/20, i have never been so disgusted in my entire life to the fact that i have eaten something that has passed its date i went back to Spar i first checked the rest what was their expiry dates you know just to be sure and just to give them benefit of a doubt that mybe it was just thus one mistakes do happen mybe they didn't see this one only. Went in and check i was so upset as every packet that was on that shelf was expired different dates and the way they handle the whole thing i was not impressed how many people who has bought this brand d and didn't realized it was it has pass it sell date, they took my details as i told them i want a proper apology from the brand Manager of hoppity poppity because i do not understand how one of their products can be in a Big Super Market shelf after it has expired 4 month ago how are they monitoring and some had 28/09/20 expiry dates. I am not happy at all i want them to apologize formally as i ate an expired products of theirs