There's many times I haven't been able to scroll down.. Had 5 of these phones in the past year.. Same problem every single time.. This phone is utter and compete JUNK..
Have you tried to hold down the trackball and firmly roll it in all directions? Could be physical debris just stuck in the trackball.
Try that all the time, it fixes things about 2% of the time for a solid 9 seconds before it gets jammed up again
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