IF you started from scratch with a factory default 200, added it to OBI, then configured to GV it should be setup properly. IF you changed things, all bets are off and it may be easier to start over.
However, you can check that Voice Services/SPx Services/X_InboundCallRoute = ph
That, and possibly your handset ringer is bad OR maybe you have too many handsets connected. I think it only support about 3 ringer equivalence == maybe less.