Hello pena0207, welcome to the Samsung Community. I understand your concerns with your left touch button not working on your device. I understand how worrisome it can be when the touch function is not working properly, but there are some simple ways to get the touchscreen working again when it is unresponsive.
If a third party screen protector or accessory is attached, the touchscreen may not work properly. In particular, it may not work well if there is dust or air under the protector, if two or more protective films are attached to the screen, or if the protective film is peeling near the edge of the screen. Remove the screen protector or film if it is peeling or has debris underneath it.
The touchscreen may not work properly if you wear gloves, have dust on your finger, or touch the screen with fingernails or a ballpoint pen. It may also not work if a conductive object, such as a coin or key, is close to the screen.
If the screen is wet, the touch sensor may not work properly. Even for waterproof models, some touch functions may not work if the product is used in water. Gently wipe the front and back of your device using a lint-free, soft microfiber cleaning cloth or a camera lens cleaning cloth. Do not apply too much pressure when cleaning the device.
Restart your device
When using the full screen gesture function, touch input may not be possible because the touch is recognized as a gesture. To stop this from happening, disable the full screen gesture function. Open Settings, tap Display and then tap Navigation bar. Tap Buttons to disable full screen gestures.
If the Touch sensitivity setting is turned on when no protective film is used, the touchscreen may respond too sensitively and therefore malfunction. To disable the Touch sensitivity feature, navigate to Settings, tap Display, and then tap the switch next to Touch sensitivity to turn it off.
Perform a factory data reset, please be sure to back up your device before performing the reset:
Navigate to and open Settings, then tap General management, and then tap Reset. Tap Factory data reset, then swipe to and tap Reset, and then tap Delete all. Your device will reset and you will need to perform the initial setup process.
If the issue persists after performing the previous steps, please contact Samsung Support to set up service.
