Disturbing service!

I am very disturbed and disappointed with the service I received from a lady at SPAR kwamashu shopping center. I bought plain yogurt on Monday 02/12/2019 and to my surprise when I have had a few mouthfuls I realize that it is off.. I check the best before date and it is use by 27/11/2019..Disapointed as I am I decide to go there early today as I had other commitments I have for day, when I get there a lady by the name of Thembsile or Thembeka I can't recall. I tell the lady about the expired goods and she just gives me my money but I specifically stated that I wanted to change it. No apology, acknowledgment whatsoever.Even asking me if I would prefer cash or an exchange. NOTHING! I am a very loyal customer to SPAR and if this is the kind of service you giving to your customers than I would need to find alternatives. I am very annoyed with the service I got.