Iphone screen replaced by apple, not working

I got my iphone 5 screen replaced by apple after it cracked...worked like new after the refurbishment, but suddenly then phone screen had numerous vertical bars on that change color when booting up/unlocking/at home screen. When the phone is restoring, the bars are at the top of the screen, only showig about 1mm of each. The bars are probably 1cm in width. I have not dropped it or anything since getting it fixed. Is there anything i can do to fix this? I've already restored twice to no avail.

Thanks