Your calls are not dropping because you are using GV. Something is not setup properly and suspect it might be a problem with your router. Changing to a paid VOIP provider might present the same problem. I don't think you should be using GV for business anyway.
My recommended VOIP providers are: Anveo, Callcentric, VOIP>ms. Of course they are a host of other VOIP providers out there. Are you located in the US?
