Doorbell 3 Battery

Hi, I have doorbell 3 battery, but hardwired it. I got a problem that the doorbell won't connect to internet. It reads offline. I have Google WiFi that gives dual bands 2.4 & 5, so that band issue is not the problem. Also, the battery was draining so badly that I have to take it off and charge it almost every week (though it's hardwired). I reseted the device and reconnected it. it got better with connection but the battery is still draining. It reads the battery is chargeing but the percentage bar is still going down!