I used the Unlawful Call Center when I was receiving about 50 calls a day from what might have been a fax machine. They were scattered throughout the day. I believe this was the reason I subscribed to caller id.
I discovered the number that had called was actually spoofed. In the end Verizon changed my home phone number without charge since the matter went unresolved.
Answered the phone and a recorded message stated that the check they had sent me had not been cashed and if I wanted to remain elligible for the funds I should press one. I hung up.