Please contact Support and provide the email address associated with your Flair account. In that email, include the device ID/name that has the battery issue. To find the device ID/name, in the Flair app, tap the Flair menu and go to Home Settings->Flair Device.
Note: Rechargeable batteries can sometimes result in false low battery alerts. When you do get these alerts, you can wait a few months before recharging.