Antenne, I haven’t sent mine back and the seller didn’t ask for it. But I guess the difference in my case was that I asked before ordering if I get a board with genuine chip and I didn’t. So when I first complained he asked me to just try it and claimed that this board is just as good. But I insisted that I wanted the original chip because it’s well tested and safe to use, whereas this one is of unknown quality. He refunded me after that. I wouldn’t have sent the board back to him even if he asked because that would cost a lot more than the board itself.
Pavithra_uk has done some testing of these boards we got. It’s not as good as original, but usable.