I've researched this but can't find good answers, hoping you nostriches can help me out. If I have phoenix wallet and want to accept lightning payments, can I go to receive and generate an invoice and have multiple people pay me with the same invoice? Can my phone be offline and then receive those payments when online, or does it have to be connected at the same second a user tries to pay me? If I have to be online, if I "swipe away" the app in Android, does having the "background service" running count as "online"? #asknostr