I'm pretty sure these are the [***] who used to call and leave messages saying they were trying to serve me papers but needed to verify my address. Like that's not how that works.... Thought I had gotten rid of them. I guess not. I have a new number to block.
They must look up the old numbers from people they are trying to collect debt from. I have had this number for over 10 years, but I looked up the person on one of those "finder" websites and they had it a few years before me. Illegal I believe but you cant prove it. Every few years I go through this as that person defaults on more stuff.