New Display, but Touch not working.

Hey,

I bought a replacement display for my iPhone 5s. I replaced the old one. Everything worked fine. Really everything. After charging it to 100% the screen didn't answer to my fingers so the touch didn't work. Everything else worked (The power button, home button, the LCD showed everything without any issue)I even restored it, but then I thought the Display may be damaged and the touch stopped working. I ordered another one. This time it did the same from the beginning on. Could anyone have an idea what is wrong with my phone? or what part needs to be replaced? I mean it works fine except the Touch sensor.