It's impossible for a properly-configured Google Voice account to ring an OBi device via Google Chat, if Chat is not checked. That means, it must not be checked on the Phones tab of Settings, and you have examined every row of settings on the "Groups & Circles" tab of Settings.
You are either missing something in your settings, or you are editing the wrong Google account (one other than the account that is linked to your OBi device).
If you can't find your error, then delete (click the trash can icon) the SP configuration that you set up with Google Voice, on the OBiTALK dashboard.
Sign out of your Google/GV/Gmail account. Clear your browser's cache, history and cookies. Close and re-open the browser. Sign into the correct Google account that holds your GV phone number. Go to the Settings page, look at the left side of the page, and confirm that you do, in fact, see your correct Google Voice phone number on the left side, under the words "Your number".
Leave that browser tab open. Open another tab, and log into the OBiTALK portal. Set up Google Voice again from scratch. When it asks for permission to use your GV account, look carefully at the Gmail address it will display, and confirm that it matches the one on the other browser tab.
After doing this, you will need to go back to the Phones tab and remove the check mark next to Chat, and once again edit Groups & Circles to re-set it to use the default phones, with Chat de-selected.
It should go without saying, but I have learned not to assume anything: also examine your OBiTALK dashboard to see if you have configured any SIP VoIP SPs to also ring your phone.
