Mr Skunk.
You should be able to tell if the thread on the puller has stripped quite easily, unless its jammed in there of course! Hopefully it is that thread and not the f/wheel thread, a new puller in place, with a little tension on the centre bolt, a 'nice' tap or two on the bolt should see it pop free. I left mine under tension for a while as it put up a fight. If the female thread has stripped, maybe you can fashion a puller to work off the flywheel holes somehow? Angled rods or tap two opposing holes with an appropriate thread to get some bolts in to work off?
I wish you luck mate, you'll get it off.
Eggsy.