The LCD looks okay but no any touch work in it, what's the problem?

Hii, my name is Ady :)

I did replacement the LCD Screen of my Sony Xperia XZ Premium but the problem even getting worse. At first before replacing it, the problem only at top of the screen. Maybe around 1-2cm the touch at top screen not working, so i decided to go to smartphone fixing shop to get it fix.

They said to replace the LCD then it replaced. They claimed that the LCD work well until i came to take the phone, i saw myself yes the touch work a couple second before they hand me the phone but then after a couple try they want to show me that it fixed, the touch not even working in the whole LCD. I waited there they tried fix the phone again and try the old LCD but now the old LCD touch not working in whole LCD Screen just like the new one.

Any idea what happened here? If the new LCD is not good/broken then why the old LCD touch not working as well when try to compare? Because at first the old LCD touch working good unless at the top of it.

Need help. Please.

Thanks, Ady.