Expired yogurt

I went to Woolies Eastgare last week Friday 04th March 2016, and they had a special running \Buy 3 and pay for 2 Yoghurts\". Before I took the yoghurts I made sure to check the expiry date on all of them and it was ok however days later I discovered some of the yoghurts were expired even with the date they had which was 12th March 2016. I had to throw away the entire batch out plus two more as they were not edible they tasted like sour milk gone wrong. I still have about 12 more yoghurts to eat and I am so hesitant of trying them out to see if they are expired or not, I mean I would have thought the expiry date was a good indicator. <br> <br> Quite disappointed at this experience!<br> "