Well first, let's isolate the problem.
Use a desktop/laptop computer's web browser, not a tablet or smartphone. Sign into the correct Google/Gmail account that holds your Google Voice phone number. Go here:
https://voice.google.com/settings][url]https://voice.google.com/settings[/url]
Look at the top of the page. Do you see your Google Voice number? If not, you're signed into the wrong account. If you do see it, then scroll down and delete
ALL 10-digit forwarding phone numbers.
Unplug the OBi device. Call your Google Voice number from some other, unrelated number,
not from your linked number. What happens? The expected result is that you, the caller, will hear about 25 seconds of ringing, and then the call will be sent to Google Voice's voicemail.
Does that work?