Same here. I called the number back within 2 minutes of receiving the call. They left no message and when I tried calling back, "The number you have reached in not in service." How convenient for them.
Call came in on one of our cell phones. Caller was a gentleman who spoke with a foreign accent and began a sales spiel of some sort. I politely declined and hung-up. No name was present on the Caller ID, just the number.
Instead make an appointment and give them the address of your local police department. Stop by the station and tell them what you did and give them the time of the appointment. Whoever comes will say they bought a list of customer contacts from someone. At least it's a starting point. As they say follow the money. Good luck ,Bob