JVC 27" Screen Issues

I am having issues with a 27" JVC television.  When turned on the screen compresses to a horizontal line in the center of the screen.  As the TV warms up the line widens showing more picture.  After about 15 minutes the screen is viewable but the bottom is still jittery.  If stations such as news with tickers on the bottem are on the ticker can't be read.  I wear hearing aids in both ears and keep the captions on to prevent from having to raise the volume to high - many times the captions can't be read either.