Low Battery Notice on a Wired Stick Up Cam?

I complained to Ring last week and they sent me out a new unit. Great customer service! Only trouble is… it has exactly the same issue!!! Set the new one up, easy, then it updated its software, all good so far… then straight away “critically low battery” warning. The camera now has zero functionality. I’m convinced it’s something to do with the latest software update. Many people have said (including myself) that the unit was working fine for weeks/months and now it’s stopped working.