It seems like your phone's display is faulty and needs to be repaired or replaced. A few things could be causing the top half to become unresponsive:
* If the phone was recently dropped, there may be internal damage to the display connector cables or components. Impact can disrupt connections.
* The digitizer touch layer that detects touch input could be damaged. This is often a separate layer from the LCD display itself.
* Liquid damage or corrosion may have occurred on the display connectors or controller chip.
* An underlying software or graphics issue is less likely since a reset did not resolve it.
Before replacing the screen, I would recommend:
* Trying a forced reboot by holding power+vol down for 20+ sec. This may reset any software glitches.
* Visually inspecting the top of the screen for cracks/separated glass. External damage points to impact.
* Backing up data and testing a restore in case it's an odd software problem.
* Reseating the display cable connections internally after reading the iFixit repair [guide|126236|guide|new_window=true].
If the problem persists after troubleshooting, a screen replacement likely is required. [br]
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Use reputable parts and follow guides carefully to avoid any further damage. This should fully restore the touch function.[br]
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[product|IF426-000]