Sour Chicken

Good day, I normally by alot of stuff at Checkers in the goldfields mall in welkom as it is convenient. I bought 7 boxes of the country fair chicken steaklet's on special recently, mushroom and garlic and cordon bleu....I have used 3 boxes already and all the 3 have been extremely sour. ..smell and taste and I had to throw them away I have 4 boxes left and I'm to scared to even attempt it considering 3 of the batch is already sour. ...and I'm so spite I threw away my till slip already as ive never experience this before.....