To be clear: you have two different OBi 202 boxes. Each one has the ability to support up to four different service providers. Are you using Phonepower on one box, and Google Voice on the other box? Or, are you using both services on both boxes, or what?
Are the calls getting disconnected on both boxes, regardless of whether the calls are carried over PhonePower or over Google Voice?
If both boxes fail, and/or both service providers fail, then your own LAN/Router/ISP are causing the issue.
Be more detailed in your reply if you would like help.