Extra Select Premium Wild Bird Food, 1 kg

Could you tell me why i had loads of little flies in the seed i did buy it in july because i use it very slowl this is the first time i have had this

The price quoted is "price: £15.49 (£0.77 / kg) & free delivery in the uk on orders over £20." so - 2 bags = £30.98. why the delivery charge?.

I tried to order a bag of this and a bag of seeds - (order > £20) but the system kept adding c £5 in postage. Free delivery?

Do the drop seed Germernate ?