We are doing a countertop remodel and just trying to unplug our stove... and we can't get it unplugged (of all things)!!

It looks like a black rectangular box and does swivel (but that does not seem to unplug it). Pulling, twisting, and cursing at it have not worked. Of course, the manual and installation schematics are no help whatsoever.

This seems like something that should be insanely simple but nothing we've tried has worked and we hate to call an electrician out just for this!! Please help!

(We are actually pretty handy, and not complete idiots, I swear; why we can't do this is beyond me!)