my touch isn't working

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Try these steps

Try using Touch ID after each step:

1. Make sure you have the latest version of macOS.
2. Make sure your fingers and the Touch ID sensor are clean and dry.* Use a clean, lint-free cloth to wipe off any dirt or debris on the Touch ID sensor.
3. Your finger should cover the Touch ID sensor completely. While Touch ID is scanning, you shouldn't tap too quickly or move your finger around.
4. Choose Apple menu  > System Preferences, click Users & Groups, then click the lock  to make changes. Click Login Options, then make sure Automatic login is turned off.
5. Choose Apple menu  > System Preferences, click Touch ID, then make sure "Unlocking your Mac" or "iTunes Store, App Store & Apple Books" is turned on, and that you've added one or more fingerprints.
6. Try to add a different fingerprint.
7. For Magic Keyboard with Touch ID, turn your keyboard off and back on again, then connect your keyboard to your Mac with the USB to Lightning cable. After you've turned Magic Keyboard off and back on again, Touch ID may be unavailable for up to 10 seconds.
8. Restart your Mac.

Try these steps. when the Mac is brand new and this function came defective out of the box, I would contact your reseller.