Product purchased was gone off

Good day, I have laid a complaint on the Checkers complaints platform twice in the last week however there has been no response to date. I purchased a Bar One and Chocolate Mousse dessert from Checkers Hyper in Pavilion, Durban on Monday, 09 August 2021. The expiry date marked on the item was 10 August 2021. The item cost was R84.99. Upon returning home and consuming the product, it was found to be already expired, i.e, the item was sour tasting, the cream had gone “off”. I have tried contacting the complaints department several times as I would like a refund for the item. I still have the original item in my refrigerator. Please can someone contact me to assist with this issue.