I googled one once after it left an obvious scam voicemail which led me to the virtual phone number providers site. I looked at reporting it on the FCCs website, but reporting there is a PIA. You have to fill out a big form to create a report. The virtual number providers site had it's own report page which took 2 seconds to fill out. Later that day I got an email saying they take it seriously, it's a Google voice number or something and they're opening an investigation. The next day I get an email saying they concluded their investigation and the number was disconnected and the account terminated. It was kinda satisfying, though I doubt it impacted the scammer much.