I have that issue with one of my VVW no matter how full my bottle is. I have to take the door off and use two hands to squonk it hard enough to get juice up into it. I've been meaning to change bottles out to see if that would fix it, but I just haven't taken the time to mess with it. It might be the O-ring causing it though. How hard are they to take off and put back on?
Valerie, When that has happened to me it is always that the tube is too long. It will suction to the bottom of the bottle when you squeeze. Pull the bottle out where you can see the tube inside. If it is touching the bottom or the sides you need to trim it.