I can guarantee that if any of us that offered advice knew that you where going to attempt this Job with a bottle full of air then I don't think any of us would have volunteered such information, The valve is stuck shut because of all the pressure behind it, Try pushing the valve again now as you have it out to see if it moves. If its buggered there are still other ways to empty your bottle without taking the valve out of the bottle,
Glad it worked out for you though but don't try it again, Lol,
I Just couldn't help imagining the brown trouser moment when the air gave way and you thought,,, OH . Nearly shat meself. Col.