Each network carrier has their own method to set up diverting back to the carrier voicemail.
It's better to have Hullomail help do this for you but first you must ensure your network carrier is set correctly within the Hullomail app by checking in Menu -> Account -> Phone.
Once the correct network carrier is set, then do the following:
On iPhone:
- Ensure Wi-Fi Calling is disabled (via iPhone Settings -> Phone -> Wi-Fi Calling)
- Open your iPhone Contacts app
- Locate the 'Hullomail Deactivate' contact
- Call the deactivation code inside - This will try set the calls to forward back to the carrier voicemail service
On Android:
- Ensure Wi-Fi Calling is disabled (via your Phone app -> Setting -> Wi-Fi Calling)
- Open the Hullomail app
- Go to Menu/Settings -> Voicemail activation
- Tap 'Deactivate voicemail' - This will try set the calls to forward back to the carrier voicemail service