Lower portion of my lumia phone's screen not working properly

[ALOK SARKAR]

Lower portion of my lumia phone's screen not working means tap is working fine but scrool is not working.....

 

[Zachary Boddy]

That's a strange issue. Have you tried restarting the phone?
What portion of the screen exactly is failing to work? Is it the entire lower half?
Are taps still reliable?