Vertical lines on the left side of screen KD55X7000F

hi guys,

i have a sony bravia kd 55x700f.

3 days ago it developed vertical black lines on the left side of the screen. my warrant has expired. i contacted the sony service center and they say the screen needs replacement. i am not sure what has brought the lines. have checked all input cables and devices. any advise to help me solve this issue will be highly appreciated.