Expanding on the simple approach above, let the caller know who they've reached. This will not only eliminate people leaving voicemails by mistake, but it will reassure the caller that they have called the number they intended.
Whether it’s an out-of-stock product, a canceled event, or social media snafu, there are times when your business may see an influx of frustrated callers. While it is important to address their concerns head-on, you may not be able to answer each call as it’s received. Make sure you use best practices for dealing with angry customers, and that your voicemail greeting sets the appropriate tone. Avoid defensive language, validate their concerns, and keep them informed as to how you are handling the situation.

There is a limit on the VM length but you can modify it. This line of the script has a maxLength parameter, represented in seconds: resp.record(maxLength=”30″, action=”/handle-recording”). If you changed that value from 30 to 120, for example, the max VM recording length would be 120 seconds, for example. Note that the voice mail recording is not stored on the Pi; it’s stored on Twilio’s servers, hence the per minute charge from Twilio for the recording and the service. Is it possible to use it as CCF (conditional call forwarding)? after enabling the forwarding option it should play some pre recorded messages on the basis of who calls ?
Do you have a landline at work? Make sure that all your phones, personal and business, have good clear, professional English voicemail greetings.