Q: Viewing my hands free call log

Hello, Can you please tell me how to view my car's hands free call/ message log? We have OnStar and Android phones. Our cell phone provider is Verizon but I was told that AT&T handled the hands free calls. We have our phones paired with the car. I contacted AT&T but they told me that it was not possible to register my car's phone number assigned by OnStar with them to see usage. OnStar said it isn't possible. Verizon said the same although these calls (through Bluetooth, I assume) go through our phones. We do not use OnStar's hands free minutes feature but at one point we did and stopped (it was not a good connection). I have verified that the minutes are never used. Is using Google Voice a possibility and how do I do it? So, can anyone please tell me how to view these calls whether it is though Bluetooth or by using the OnStar call minutes? We have gotten calls coming into the car but don't have enough time to write the number down if we can't answer it. Thanks!