Maybe this will help someone who will make the same mistake as I did.

When adjusting the head stay turnbuckle, the jib halyard should be tied around the foil, and the foil and torque tube  raised to provide access to the turnbuckle. If the halyard is not sufficiently tied off to the foil, it may allow the foil and the a torque tube to slide back down the stay. If the turnbuckle swage stem happens to have an outer diameter that matches the hole diameter in the foil extrusion, the foil will press fit itself onto the turnbuckle. No amount of tugging, twisting, applying tension from a properly re-tied halyard or four letter words will separate the foil from the turnbuckle. 

I called Schaeffer Marine and found them to be very helpful. I was glad to hear they have received other such calls and I wasn't the only one who didn't tie off the halyard properly. 

The fix is to remove the sail feed fitting from the foil. Two hex screws clamp this on to the foil. This will expose about an inch of the forestay. Spray penetrating oil on the stay and it will run down to the turnbuckle stem. Reattach the sail feed. I let the oil sit for a day. Slide the torque tube up the foil to just below the sail feed and tightly secure it with its two hex screws. Tie off the halyard tightly just below the sail feed and apply tension to the halyard. With a rubber mallet,  or with a hammer and block of of wood, hit the bottom of the torque tube with upswings, impacting it around the entire base. When you note that the foil is beginning to free itself from the turnbuckle, ease some halyard tension so that when the foil finally separates from the turnbuckle it doesn't shoot up the stay and pound into to the stay's masthead fitting.

Hope this serves as a useful reference to others who in the future do not securely tie off the jb halyard.

The attached photo shows the halyard attached to the torque tube shackle. Note that this cocks the torque tube which can add to the difficulty of freeing the foil from the turnbuckle . Tie the halyard to the sail feed to keep things aligned on the same axis.