I agree, sending the camera/attached lens anywhere is not an appealing alternative. Is there a friendly Nikon Dealer nearby, preferably one from which you bought either the camera or lens, that you could take it too?
Has the camera/lens ever sustained a hard knock that might be causing a jam? Many (most?) lenses will wiggle (rotational/clock-wise and counter clock-wise) a tiny bit when on the camera. Although this causes a bit of concern among some, it is perfectly normal, and unless extreme, does not effect picture quality. Does your lens have any rotational wiggle that might indicate that it is not jammed? You might try turning the camera/lens back and forth a bit with the bayonet mount unlocked. With the 500mm, I am never sure if one puts the lens on the camera, or the camera on the lens.