before trying to de-head it(pretty sure there press fit)i would check your spring and
threads and maybe use some
Noaloxon them,i had one of my SS z-max's stop working just like that once,popped the spring out and washed it and cuffed it up a little with scotch-brite and then lubed the threads with the noaloxon(you can get it from home depot,or provape) put it all back together and has worked since.
if all else fails and you cant return/exchange it you probably going to have to rap some cloth around the head (to help protect it from scratches) and grab it with some pliers and try to wobble it back and forth til it comes loose.