Why did you grind them out in the first place? When they did not fit, I would have taken them back. Most every set of brakes I have worked on, on semi-floater axles have been hub-centric which is made real obvious by how tight they fit on the axle and the lug holes are always a bit bigger then the stud.

Take them back, why should they? On the other hand, are you not going to tell them that they gave you the wrong ones in the first place so you modified to make them work? Now you want your money back for a drum that you made into junk. In my opinion, you are going to eat the cost because of a mistake you made. If you take them back and do not tell them you modified them to make them work, that is being very dishonest. Remember, what goes around comes around so eat it and learn from your own mistakes.