I bought a U.S. Masters fretless neck for one of my Masters basses. It was the only source for those basses, as they have a simple, but unique attachment method. When it came, it was lovely, but the side dots were in the wrong place, between, not on the fret position.
I pointed this out and they were very apologetic, and sent me a correctly made one (eventually, took ages!) But didn't require me to send the other back, which was nice. The bad neck now wears Luminlay side inlays in the correct position....