Hi:
Do this: open a laptop/desktop computer's web browser, not a phone or tablet, and go here:
https://voice.google.com/settingsAt the top, you should see "Google Voice number", with your GV phone number displayed next to it. If you don't, then either you are logged into the wrong Google account, or your Google account doesn't have an inbound GV phone number. Without an inbound number, there is no number to send as caller ID.
If you do see your GV phone number, then press Ctrl-T to open a new browser tab, and sign into the OBiTALK dashboard. Click on your OBi device, then click on the Service Provider (SPx) on which you set up Google Voice. Get past the 911 warning. On the window that pops up, click the link next to "Replace Google account credentials", and follow the instructions. Look closely at the Gmail address that the OBiTALK portal pops up, and confirm that it is the same Gmail address that holds your GV number, as shown in your other open browser tab. Complete the procedure and wait for your OBi to reboot.
Try calling someone and see what happens.