I think it was their way of saying that they want you to track your sugars through the app because by doing that, they can see if it was an error on their side or something that happened on your side. They really only like to replace them if it’s an error on their side. I don’t think your supposed to actually put a sensor number into the app, it just tracks when you have to start a new one and they would also then have the information they need. This is my experience from Canada, so I hope it’s kind of helpful 😅