Battery issues


So we got a ring door bell plus around 2/3 months ago. I have charged the battery twice and it’s worked fine. However, when I’ve tried the charge it last few days, it has not worked. I’ve tried using different charging outlets, refreshing the app, ringing the bell etc. the battery life just stayed the same even after hours of being plugged in and even when the battery is out of the doorbell, the green light continues to be on when attached to nothing.
I have bought a backup, but has anyone else experienced this or I have I been unlucky to have a faulty battery? I can’t afford to be spending on buying a new battery every couple of months.

Thank you!