Food spoil before the expiry date

Kasegriller sausages get mold while refrigerated before the reaching the use by date. I wasted my money here, I thought I’m buying from quality food store but it is more like the somalians food shops they sell to make sales with no interest of the product and quality of the food they sell. On Sunday the 6th April I wanted to prepare these grillers for breakfast and found it had mold and the use by date is 8th and 9th April. Disappointment is an understatement.