Pathetic unacceptable

I bought 20 sachets x 1 litre Douglasdale milk on Saturday 28 November 2020. On Sunday 29 November when I opened one sachet it was thick sour milk. I checked the best before date and it was 22 November 2020 but it was on the shelf on 28 November 2020. We checked all 20 sachet's best before date and only 5 of them the best before date was 5 December 2020. Yes, I did not check the best before date on Saturday because it was month end the shop was very busy and I was in a hurry. My partner phoned Maggie on Sunday 29 November 2020 and she said its fine we can bring 15 sachets which dates had expired we will be refunded if we bring the till slip along. When my partner visited Shoprite on Monday 30 November 2020 the manager said she doesn't believe the sachets is Shoprite's property. But one of the packers said, yes, someone working with him said they should put that expired milk on the shelf nobody would notice it. Really? This is unacceptable. And there was not even 15 sachets of milk to change the ones we want to replace. We are staying on a farm so we had to travel all the way to Zeerust to exchange the sour milk and we couldn't get 15 sachets again. So we have to travel again to Zeerust to replace that 15 sachets of milk.