Oh man, I don't blame you if they kept challenging your complaints as a paying customer, however large the language barrier is.
Well their response was, getting a bad block or a bad backplate was possible but getting both bad was impossible.
I took a pile of pictures and they said the block was 'acceptable' to them, and only the razor lip on the back plate was no good.
Luckily for me PPCs warrantied both, I got them to swap the Bitspower block for me. It has some evil design aspects but the surface finishes were smooth at least.
I gave EK another chance, I ordered a nickel plated backplate for the VII from them. It's shiny and unlike the really thin black anondizing, it's not translucent... lol
The issue is that it's covered in the same cutter marks. The cutter marks are because they are pushing the cutter on the CNC to hard so it's tipping and you can see every path it took. So it's definitely not a production error, it's a choice. Their lack of caring about the feedback, there was no language difficulty in that blow off... :-(