If you use a Google Voice number for business, and forward your calls to your mobile device, Productive works perfectly. All you need to do is forward your Google Voice calls to your cellular number, and ensure Caller ID settings are set to push the incoming caller ID to your mobile device, and not the Google Voice number.
This can be done by following Google Voice's guide on how to ensure the incoming caller's Caller ID is being forwarded, and not simply your Google Voice ID number.
STEPS:
On your computer, sign in to Google Voice
At the top right, click Settings
On the left, click Calls.
To show your Google Voice number on the device that receives a call, turn on Show my Google Voice number as caller ID when forwarding calls.
To show the caller’s phone number on the device that receives a call, turn off Show my Google Voice number as caller ID when forwarding calls.
Tip: To help you identify calls that are forwarded from Google Voice, turn on Show my Google Voice number as caller ID when forwarding calls.