They aren’t giving out information on a debt

They just call saying they’ve unsuccessful at reaching them. They ask to leave a message or them or if we have another contact number for them. I am pretty sure my brother in law never used us as a contact or reference. He never calls our home phone. He calls his brother in his cell, my husband. The cell number he calls isn’t even registered to us…it’s a work cell. My guess is they used a public search for relative related to my brother in law. Our home number isn’t listed with the phone book or online phone books so I wonder how they got our #. I think next time we get a call, I will ask.