Yay, it’s working now. I’m not sure what tech support did to the systems behind the scenes, but I was finally able to set up and add the HomeBase. I’ve now added the cameras, and have one temporarily set up on my patio watching the cats! Thanks @AnkerSupport and everyone who contributed to this thread.
If you’re still having problems be sure to call technical support. If you get on to Ashley you’ll be in good hands and she’ll make sure your problem gets solved!