Terrible Customer Service

I purchased fresh milk at the shop, upon arrival at home I discovered the milk was sour. I then had to get into my car to exchange it, thought the expiry date said 18 Dec 2021, all other milk by Douglasdale had the same expiry date. The manager refunded my money R25. 99 and refused to give me another brand, unless I pay the R4 difference. How pathetic. I spend money to return the old milk and he made a fuss over R4