Glad to hear you are enjoying Keep! It’s an excellent notes app!
If your phone ever gets lost, here are the steps I would recommend you taking: first, I would recommend trying to locate your device using Find My Device. From there, you can locate, lock, erase, and ring your lost phone. If that fails, I would recommend opening a support ticket and having them blacklist the IMEI so it can’t be reactivated. Once all that is done and you have a new phone, all you have to do is sign into the Republic app on your new phone, follow the prompts in the Republic app, and choose the option to “Move (XXX)-XXX-XXXX [your number] to this phone.” That will move your number over and deactivate the lost/stolen phone. It’s important to note that if you cancel your old line before activating your replacement phone, you will lose your phone number and there are no guarantees that it could be recovered.
I hope that answers your questions!