Got a call/voicemail from this number looking for someone else unknown to me who probably had the phone number before me (2-3 or more years ago). Call had a very threatening tone and they did their best to imply they were law enforcement without saying so. Even said if you don't respond, I suggest "you get your affairs in order" implying the person would be facing jail time which doesn't happen for debt collection in TX and I think anywhere else in the US.
Can't be 100% sure it was debt collection but I would be it is.
All in all, appeared very sleazy, and a good chance illegal under the federal Debt Collection law. If these people call you, I would check out the Law. There are decent penalties violators can be forced to pay you. I would also report them to appropriate State/Federal Agencies.
Identified themselves as "James Hawkins" with "Legal Services"