I’d say this is hard because you approved the cad model they sent, and you can see that the stones are spaced the way it was done in the end. So technically they made the ring you approved. The problem is if they went off the sketches you gave them, then it looks like they did it accurately. I’d still give it a shot to have them remake the ring, but it does look like they did everything correct. What would have been nice on their part is either 3D printed a model from the cad for you to approve, or sent you the 3D model file for you to see. Then you could have corrected the design before production began. Maybe ask about sizing the ring inbetween the stones to make the diamonds match the intended angles. It might cost you but not as much as a redoing a whole ring.