Sometimes it’s a piece of grass or dirt gets in there. If you have some compressed air, try blowing some in there to dislodge it. If that doesn’t work, hit it with a bit of WD-40 or if you don’t have that, a bit of lubricant. If none of those work, then you are back to banging it a bit.
If this is the original shaft with an adapter that came with the driver, you shouldn't have any issue extracting the hosel adapter. Take out the hosel screw completely off the head, don't lose the washer that came with it at the bottom of the screw.
Hold the head in one hand and the grip in another, twist ( tug) gently to let loose the shaft. Never force it or ban it on the floor. If that does not do the trick, take it to the nearest authorized dealer to have them extract it.
There is no reason why the adapter won't come out freely, even if it is brand new.
Did you try the Ping customer service line ( email or phone in ) ? Maybe there is an issue with the quality control of this batch of adapters.
Some after market adapters are not fitted well. As like everything else, never force it if it is a really tight fit and doesn't want to go in.
I hope no one installed the shaft while the epoxy for the shaft was not fully cured. That would require a little heat to soften the epoxy for it to get loose.
I have this problem with Ping drivers, specifically G400 and G410 all of the time. They get stuck more than just about any other in the lab. Super easy to fix though, do as was mentioned above and bang it on the ground a few times. Grass works fine. Or, if you don't feel comfortable with that, put the head cover on it, have someone hold one end and pull and twist at the same time. It should pop off.