My Maltipoo refuses to eat his dog food!?

We buy all kinds, mostly from the vet or petco-Nutro, pro-plan,Eukanoba, Iams, Beneful,Science Diet, some all natural holistic crap.
We get him the good expensive stuff, but we gradually mix it in. We offer it as treats to encourage him, we mix in cottage cheese, sometimes rice or scrambled eggs or wet dog food. He wont touch it!!! We literally have like 6 bags sitting at home This is ridiculous. I feel like opening his little mouth and shoving it in there!! He will eat anything we give him- even bland stuff like potatoes. But not his tasty Lamb and Vegetable gourmet dog food! Yeah holistic is not crap, but i forgot the name of it.