Trap Call is a great service with some exceptions. However, the service is not great if you utilize Google Voice for everything. One maybe asking what is Trap Call, and why would one want it? Well, this service was looked into for the desire to unblock anonymous calls. The concept is simple. An anonymous caller calls the phone. You reject the call, and it is sent to Trap Call for removal of the CID block. The call is sent back to you displaying the phone number.
This requires call forwarding if unavailable – so many MVNOs will not support the service. In addition, some prepaid service plans will not support it neither. Now this requires a person to reject the call so it is forwarded. This is a slight problem as some people may find this a bit of more tedious work. There is an Android, and iOS app which I can only assume will automate this process for you.