Alarm pro base station is rendered inoperative by battery removal

I've had some trouble setting up my new alarm pro and wanted to try shutting it off and turning it back on again. The backup battery was preventing me from completely shutting it off, so I removed it. This wasn't difficult. There is an access door. There are no warnings on this access door about not removing it. It's a battery pack that pops out and back in again. Very ordinary. But when I turned it back on again, the Eero router would not function. I finally resorted to calling customer support. They told me that removing the battery has rendered the device useless. Really? I mean, seriously really? It's a replaceable battery pack. You're honestly telling me that this thing is now a paperweight? Come now, I know there is a way to replace this battery and still be able to use the thing. How do you do it?