What's up with Montego?

I have been experiencing problems with the Classic 25kg for the past 3 months. I buy 2 bags every month. In august one of the bags i bought was covered in green mould when i opened it, the other was fine but both seemed less in weight. I throw all my pellets into a plastic bin after purches. I only got about a third of the quantity i usually do. In September both the bags i bought were also covered in green mould. Of the 2 bags that i bought for September, i have only opened 1 and it was ok up until it was about half way. It started moulding after that. I have been buying Montego Classic for the last 3 years and have never had this problem. Can someone tell me whats going on? Im loosing a lot of money because of this and montego is the only pet food that doesn't give my dog allergies