Cadbury - My big box of dairy milk was properly stored in a hygienic place for some weeks and it was not expir

My big box of dairy milk was properly stored in a well drying area and in a refrigerator for some weeks..and when i opened it i found all the small packets of daily milk chocolate inside the big box were making smell on opening them and having a rotten like smell and texture..their were more than ** small packets of dairy milk in that box and literally all of them which i opened were the same.