I see. Well, let's try to troubleshoot it, then.
Log onto the Google/Gmail account that holds your Google Voice number, and go to the Settings page. Do you see your inbound Google Voice number displayed? If not, then either you are looking at the wrong Google account, or your number was reclaimed (taken back by Google for lack of use).
If you see the number, then continue. If not, then stop and reply.
Leaving that web browser tab open to your Google Voice settings page, press Ctrl-T to open a new browser tab. Sign into your OBiTALK account and look at your device (expand it if necessary, to see the status of the service providers). If you have a working Google Voice connection, it should show "Connected" status. Does it? If not, stop and reply.
If anything other than "Connected" status, then click the SPx and, on the next page, click the link to re-authorize your OBi to your Google account. When doing this, you must make sure to examine the Gmail address it displays during the authentication procedure, and confirm that it is the same as the Gmail address shown in your other browser tab, with the GV number.
Did that work?