It's striking a balance point of pain:
On the one hand: Suck it up, with the thinking "This is typical import machine quality" and keep it. I'd consider leaving the voids as they are, with it likely that they won't be an issue, OR, look into possibly brazing the void (though I admit a concern about heat distortion).
On the other hand: There's fighting the system, raising your blood pressure and stress, trying to correct the situation, risking damage on its way back to them. AND, assuming you get a replacement, there's no guarantee that it'll be any better.