Reset the Monimoto device:
MM1, MM2 - connect it to a computer (or just a charger) with batteries inserted for at least 13 seconds.
MM5, MM6 - press and hold the button next to the SIM card with batteries inserted for at least 3 seconds.
Monimoto 7 - press and hold the button on the backside of the device with batteries inserted for at least 7 seconds.
Monimoto 9 - press and hold the reset button for 14 seconds until the LED blinks blue, turns off, then displays solid blue and red simultaneously for a moment
If you have an iPhone, please go to your iPhone's Bluetooth settings, click on your Monimoto device and choose 'Forget the device' (if there was a paired device).
Finally, go to Monimoto app - create a new account and setup the Monimoto with your phone like you did first time.