Facebook is investigating a toll-free number that's circulating the web, claiming to connect you to Facebook's customer service center.
The group behind the number is not associated with Facebook in any way, and uses the fraudulent number to run a scam.
According to Google data, "Facebook customer service" gets searched, on average, about 27,000 times a month in the U.S.
For the record, if you're ever looking for Facebook's REAL customer service center, it's located here. There is no phone number to call, only online services.