Have they tried a bit of heat on it? As long as they don't superheat the crank trying to get it out, a little heat might help out. Did you put any type of locktite on the bolt when putting it in?
Also, if they haven't dealt with this particular bolt before, then they may not be used to the fact that it's torqued to close to 200 ft lbs by the time you TTY it. A good 1/2" impact wrench is usually all I need to pull one off.
Thanks,
Rick
