And if you find that you mute your phone accidentally, you need to unmute it then you can hear the sound. 1. For iPhone users, they can go to check whether the Ring/Silent switch is turned on. If the switch shows orange, that means your phone is in the silent mode so you need to toggle the button to turn on the Ring mode.
Is there any way to retrieve the voicemail greeting from a smart phone after the service has been stopped to the phone?

If the airplane mode method doesn’t work, make sure the voicemail has been deleted from your network.
Android phones can access voicemail by holding down the 1 key on the dial pad until the phone dials your 10-digit phone number. You will automatically connect to your mailbox and be prompted to enter your temporary password; this password is the last 4 digits of your phone number followed by the # key. Start the Google Voice app. Tap the three horizontal lines at the top left of the screen (sometimes called a hamburger menu), and then tap “Settings.” In the Voicemail section, tap “Voicemail greeting.” Tap “Record a greeting.” How do I access my voicemail? To call your voicemail on an Android phone, simply open your phone’s dial pad and hold your finger down on the “1” key. You can also call your voicemail from a different phone by calling your own number and tapping the pound key. How do you check your voicemail?