A very nice GM helped me out once. I was fighting a puk and ended up being backflip-kicked onto a spot where I couldn't do anything except spin in place. The GM moved me to an aetheryte to solve my problem, and he was a pretty awesome conversationalist, too.

As I understand it, GM's absolutely help players, but only in very specific situations. Those are listed on the GM call screen, and there is definitely no mention there of fixing bugged mobs.