This is a scam. Do not provide them any information.
They called me repeatedly looking for my mother, I would tell them they had the wrong number and they would call back 5 minutes later with the same story of working for a law office and collecting a debt.
I continued to push them for information and they hung up on me. I called back and demanded their full address, company name, their personal name and a phone number. They gave me the address of a law office in South Carolina (which when I googled the address came up as a completely separate law office than who they said they were affiliated with), so I contacted the office. The lawyer had no idea what I was talking about and said he had no affiliation with the company.
Also, I called the number who had been calling me back and threatened to involve the police because I thought it was a scam. They quickly changed their story to 'oops, looks like we contacted you in error, I apologize'.
I'm submitting their info to the CFPB.
The other number they call from is 855-584-6183.