1) How to reset Z3 / TEVI?

Please follow the below procedure to reset TEVI:

A) Forget the Z3/ TEVI Bluetooth name, LYPERTEK Z3 / LYPERTEK TEVI - L / R,  from the bluetooth list on the phone.
B) Put both earphones into the charging case; (make sure the charging case has power)
C) Press and hold both Z3 / TEVI L/R for 5 seconds.  Make sure you can see the light.
D) Once you see the light flash, release the fingers.  Then Z3 / TEVI was reset.
E) Take out both earphones from the charging case, LED of one side earphone is flashing, which means it is at pairing mode.  
F) Follow the pairing procedure to connect Z3 / TEVI with the phone again.

2) Can I use only one side?

Yeah, TEVI can be used individually. 

A) Take out both earphones from the charging case.

B) After TEVI connected to the phone.  Then put one of the earphones back to the charging case.

3) The white LED is continuously blinking?

Please try to RESET.

1) How to reset SOUNDFREE S20/LEVI.

A) Press and hold 3 seconds to turn off both sides.

B) Press once to turn on both sides (will see the white LED blinks.) At the same time, press and hold both L/R buttons until seeing the LED turns to white/red blinking on both sides. Then enter the pairing mode.