I recall one bloke who had this problem subsequently found his was welded in....
Do you have a hi-lift jack? You could back up to a telegraph pole, wrap a strap around the pole, put an eyebolt through the towball hole and jack it out? I'd be using chain or something non elastic though, you don't want it springing out and flying around when it finally gives.
Or, if you were a farmer, chain it to a tree and try to drive away
The Hitchhiker's
guide to the the Triton universe and NTN.
A how to on finding your own way -
search me.
The two threads I wish people would use more:
thing 1 and
thing 2.