if the Ford GN hitch works like my Ram you not only need to raise the lever but also turn it 90 degrees to release the ball keepers in the ball shaft
It might be rusted in place as I think was eluded to by the previous post. Can you rotate the ball in the socket? If you can its not rusted tight. Raise the lever, rotate the lever and perhaps tap on it lightly to free things up.
Doug & Cindy
2014 Cedar Creek 36ckts, Disc Brakes, EMS, Trav'lr, 20k GooseBox
2018 Ram 2500 CCSB CTD 4x4 RASS