Definitely follow up with a formal complaint to law enforcement as Alfalfa said. Also look at the complaints this "company" has on the BBB's site and how they respond to them. Whenever someone challenges them forcefully enough, they simply back down and delete the file. They never offer any proof that any of these so-called "debts" are real.
I received a phone call from this number, but no one said a word. I also believe this same person is calling me from a blocked number at very early times in the morning, like 4 a.m.
It's a collection agency, but they don't say anything when they call. They just call to annoy people. In my case I just got a new phone number and the person they are trying to harass is the last person who used the #.
These people continues to call my landline but leaves no message. Called them back early saturday @ 6a and it was a collection call from first national collection at www.fncbinc.com. hours of operation are 6a -6p M-F pacific time.