So just an update, I contacted OBi support and we ran some tests and they couldn't come up with a reason for why the issue was happening. They sent a replacement on Friday afternoon and I got it today, plugged it in, set up the google voice service on it, and it worked, just like the other one should have. No issues or anything.
I compared both of the OBi boxes, and I noticed the first one had a scratched up label (the one on the bottom of the OBi) and a missing screw cap, remember that I've had the OBI for 5 days, counting today so I can only think that the OBi was either used or defective from when it was sent from Amazon. Regardless of why it didn't work, I'm more than happy with Obihai Support. Couldn't have asked for more!
jimates: I ran into the same problem you were having with my DIR-615. I gave my OBI a static address on the router and then went to advanced tab and created a PORT FORWARDING RULE, opening all TCP and UDP ports, 1-65535. It has not dropped any calls since I did that. Just in case any else is getting dropped calls.
Thanks to all!