I had my service with Vonage briefly but after I experienced their services I reverted to my local land line provider. That was over 4 years ago.
To this day, active/current Vonage customers are unable to call my number. When they do they get the message "This number is incorrect or is no longer in service. Please check your number and dial again".
All other customers (land line, cell phone, other VOIP phones) are able to contact me at that very same number. My local provider has told me that this is a common problem with Vonage and that Vonage has chosen to ignore it.
Review about: Vonage Phone Plan.