On that GV setting page where Chat is ticked, click on the edit button immediately below the email address. Check that the Ring Schedule has appropriate values.
If still no sucess, need to determine which of these two is happening.
GV is not forwarding calls to your OBi.
or
GV is forwarding calls to your OBi, but something is amiss with your OBi/phone.
If you don't know the IP address of your OBi on your LAN, dial ***1 and it will be read out to you.
Point a browser at the OBi's IP address and log in. admin and admin are the default name and password. On the left hand side click on Status, then click on Call History. Do you see the missed calls from GV?
Also try dialling your GV number from another phone (eg a cellphone) while observing the PHONE LED on the OBi100. (That is the right most one.) Does it begin to flash?