Why does (only) the lower part of my touch screen not respond?

I regularly order aftermarket Sony screens, the only stock available in the US. I also order OEM Sony screens from a Sony authorized vendor in Europe. The Sony OEM often costs 5 times as much, so my customers rarely choose this option, despite my encouragement to go OEM.

The aftermarket screen out there really are not great quality. Defective digitizers are highly common. Glass quality is often poor too. Asahi Dragontrail Glass (a Gorilla Glass alternative) is only found on the OEM parts. Aftermaket is usually cheap tempered glass.

I have never seen a defective Sony Service Pack screen.

Regardless of which part you use, I recommend a professional familiar with Sony. Sony is basically the last brand learned by most repair texh in the US, so few even know what they are doing.

Definitely go to a place that can inspect your motherboard under a microscope first. It is entirely possible that the digtitzer connector on the motherboard is damaged due to the repeated mashing efforts of someone.