Upload & Sell: Off
Tell them to fix your outer focus point and be done with it.
Microcracks in your mount are a NON-issue for normal use.
Mostly it's because you hold a heavy lens at the camera and not the lens.
Got that with my D7000 too because I used to use the normal Nikon strap with it and thus constant pressure on the mount with my 70-200 2.8. Now I use a BR strap on the lensmount and no problems at all with either (repaired) D7000 and D800E.
When I got the 5D2 I also had cracked mount (so said Canon). Also due to the same cause as mentioned above I suppose. Then I decided to jump ship (temporarely to D7000 and now D800e), but it seems like it's not much better here for repair, IQ and autofocus is worlds apart. (you are lucky btw, it's only 250, I had to pay 400 + shipping for the mount on the 5D2, it seemed like they replace the whole front of the body)
The D7000 was around 300 for the mount and front of body replacement (showed cracks in the body itself).