If we all needed to have a strong knowledge of bloodlines and pedigrees then about 95% of this board would not be able purchase any dog.
We all start somewhere.
What she paid for the dog is no one's business. I have paid more than that for a dog and we all have our reasons for doing so. Granted, mine was titled, breed surveyed, and exceptional in several ways, but it is what it is. Heck, I'm just thinking that if this dog is 10k, then the one year old I've been thinking of selling should easily go for 15k. LOL LOL
The language barrier comment is asinine. The dog will listen when he respects his new handler.
While I see no point in someone like the OP importing a green dog (there are a zillion of them right here in the US and she doesn't have particular requirements that can only be met with an import), I also see no point in making a federal case of it. Maybe there is something about this dog that spoke to her, the way you can sometimes see photos of puppies and have one stick out as "THE ONE," based on a 6th sense and having nothing to do with logic. Most of us are guilty of that at one time or another. Emotion does play a role sometimes.
Honestly, I'm more concerned that the dog had to be tested, meaning they didn't know him that well. (Correct me if I'm misreading this). I have a 1yr old I'm thinking of selling that I KNOW is ok with Chihuahuas and small children because that's what I live with. I also KNOW he is protective and serious, and not playing a prey game, because I live with him and have seen him in many many situations over the course of his short life. Having to pull a dog out of a kennel to "test" him for a situation like the OP's is a little disconcerting to me because the OP is likely to not have the knowledge of what to do when he acts totally different in a different situation, as dogs are known for doing!