well here's what i did when this happened to me.
i loosened the clamp all the way and just stomped on the deck as hars as i could while holding the bars but it has to be off the ground obviously.
it should break the starnut and be able to be pulled off
I tried that but I didn't have a vise so I put the a tube between the fork legs and started spinning the bars but the bolt was just spinning with the bars.
Break the ICS cap or drill the bolt out... there's really not that much to be done. Last case scenario buy an SCS and cut your bars off with a saw, 2 inches up.