A Google Voice telephone line, the creditor really has no idea who owns it nor where they live. As others mentioned, unless it is by first class mail and in writing, just ignore it.
Sometimes it is the insurance company's fault too. I got a bill recently for a charge that I know is 100 percent covered by medical, since the entire family already met our out-of-pocket maximum for 2019. When I called the insurer they said the doctor billing it is not "in plan" so they don't have to pay. But it was a radiologist who works for the hospital, to read X-ray charts taken in the hospital. So it is 100% covered. The insurer agreed and will pay the doctor regardless he is in plan or not, because it was a hospital procedure.
Read the fine print, and never assume your health insurer is on your side.