iPhone 5s has multiple lines on screen after multiple LCD replacement

My old screen was damaged and the battery was not performing well, so I had it replaced. However, after replacement, I have discovered that the new battery was draining so fast even on standby. I had no choice but let the repair guy put back the old one. Then a problem occurred — when the LCD was put back in the phone, multiple vertical white lines in different thickness appeared. The guy doing the repair had the LCD replaced by two new ones already but still the problem does not cease to exist. Is it still a problem on the LCD? What’s causing those vertical lines?