Mouldy food

I have been a loyal montego customer for the last 5 years. And is extremely disappointed in what has been happening in the last 2 months I purchase the 25KG adult montego on a monthly basis for my dogs but nowadays the food becomes mouldy after a week and a half. My dogs poo is also moist and this has never happened I thought I did something wrong and tried other ways but its definitely the food. I am dissatisfied with the fact that this is haplening to me as a loyal customer. Please advise on the way forward.