Maybe he just doesn’t like that particular brand? Or flavor? I know that our cat absolutely hated one particular brand for no apparent reason but had no issues with other brands in that same price bracket, and even with the other brands there was one flavor he just hated and would rather starve himself than eat. Your dog doesn’t know the price tag on that food. All he knows is that he doesn’t like it. He’s not being spiteful, he’s just… being a dog. Just switch to another brand.

so buy him a food he likes. animals have preferences and dislikes too

Maybe your dog doesn't like the texture of the food? My cat won't eat canned morcels in sauce. He only eats paté, dry food, and dry food pockets with paté inside. Try giving your dog food with the same consistency as dog shit a.k.a. canned dog food or rehydrated kibble.

So, is dogshit more or less expensive than $30/kilo? I haven't priced it lately. I know that bullshit is getting more costly every day.

Bring the bag back to the pet food store. Most have a policy that they’ll take it back and give store credit if your dog doesn’t eat it. Then you can try another type of food. You can also ask the store employees for samples, if you want to make sure your dog will like it before buying another bag. After my dog was hit by a car, she turned incredibly picky with her food. It took 2 months for us to find a food (and food topper) that she would eat. In the mean time, you can also give some plain baked chicken and rice (and if they’ll eat carrots or other veggies, sneak small pieces into the chicken and rice). I haven’t met a dog who won’t eat that!