It's possible that the THUMB device is in Lockout mode, which is designed to prevent accidental activation in pockets or bags. When in Lockout mode, all functions are deactivated.
Before proceeding, please ensure that the device is fully charged. The power indicator will turn green at the end of the charging cycle.
To exit or enter Lockout mode, press and hold both switch buttons simultaneously until the red power indicator flashes.
Please let us know if this resolves the issue.