Rotten milk spar brand

I bought 5 boxes of 6 pack fresh milk spar brand and one pack of 6 boxes is expired and due to covid19 i cant go to the shop and return it and get my refund in fact im thiking of taking all 5 pack back and ask for my refund. I have a slip and for a big customer like me this is disappointing and embarrassing for such an big shop to sell rotten things is beneath me so i dont even know if i want to buy at spar anymore and i hope their milk is not all rotten cause other people wont say anything.i hope i get my money back i hope i wont have to shut down the store due to rotten food being sold.